U.S. patent application number 13/328675 was filed with the patent office on 2012-06-21 for geopolymer composite for ultra high performance concrete.
This patent application is currently assigned to The Catholic University of America. Invention is credited to Weiliang Gong, Werner Lutze, Ian Pegg.
Application Number | 20120152153 13/328675 |
Document ID | / |
Family ID | 46232672 |
Filed Date | 2012-06-21 |
United States Patent
Application |
20120152153 |
Kind Code |
A1 |
Gong; Weiliang ; et
al. |
June 21, 2012 |
GEOPOLYMER COMPOSITE FOR ULTRA HIGH PERFORMANCE CONCRETE
Abstract
A geopolymer composite ultra high performance concrete (GUHPC),
and methods of making the same, are provided herein, the GUHPC
comprising: (a) a binder comprising one or more selected from the
group consisting of reactive aluminosilicate and reactive
alkali-earth aluminosilicate; (b) an alkali activator comprising an
aqueous solution of metal hydroxide and metal silicate; and (c) one
or more aggregate.
Inventors: |
Gong; Weiliang; (Rockville,
MD) ; Lutze; Werner; (Chevy Chase, MD) ; Pegg;
Ian; (Alexandria, VA) |
Assignee: |
The Catholic University of
America
|
Family ID: |
46232672 |
Appl. No.: |
13/328675 |
Filed: |
December 16, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61457052 |
Dec 17, 2010 |
|
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Current U.S.
Class: |
106/705 ;
106/638; 106/789; 106/811; 106/813; 106/814; 106/816 |
Current CPC
Class: |
C04B 28/006 20130101;
C04B 2201/50 20130101; Y02W 30/91 20150501; Y02P 40/10 20151101;
C04B 28/006 20130101; C04B 12/04 20130101; C04B 14/00 20130101;
C04B 14/041 20130101; C04B 14/38 20130101; C04B 22/062 20130101;
C04B 28/006 20130101; C04B 12/04 20130101; C04B 14/06 20130101;
C04B 14/106 20130101; C04B 18/141 20130101; C04B 18/146 20130101;
C04B 22/064 20130101; C04B 28/006 20130101; C04B 12/04 20130101;
C04B 14/106 20130101; C04B 18/08 20130101; C04B 18/141 20130101;
C04B 18/146 20130101; C04B 22/064 20130101 |
Class at
Publication: |
106/705 ;
106/638; 106/814; 106/811; 106/789; 106/816; 106/813 |
International
Class: |
C04B 28/26 20060101
C04B028/26; C04B 18/06 20060101 C04B018/06; C04B 28/08 20060101
C04B028/08; C04B 14/22 20060101 C04B014/22 |
Claims
1. A geopolymeric composite ultra high performance concrete (GUHPC)
mix, comprising: (a) a binder comprising one or more selected from
the group consisting of reactive aluminosilicate and reactive
alkali-earth aluminosilicate; (b) an alkali activator comprising an
aqueous solution of metal hydroxide and metal silicate; and (c) one
or more aggregate.
2. The GUHPC mix of claim 1, wherein the binder comprises about 10
to 50 wt % of the GUHPC mix.
3. The GUHPC mix of claim 1, wherein the binder comprises one or
more reactive aluminosilicate comprising about 0 to 30 wt % of the
GUHPC mix.
4. The GUHPC mix of claim 3, wherein the one or more reactive
aluminosilicate is selected from the group consisting of
metakaolin, reactive aluminosilicate glasses, and ultrafine Class F
fly ash.
5. The GUHPC mix of claim 1, wherein the binder comprises one or
more reactive alkali-earth aluminosilicate comprising about 2 to 40
wt % of the GUHPC mix.
6. The GUHPC mix of claim 5, wherein the one or more reactive
alkali-earth aluminosilicate are selected from the group consisting
of granulated blast furnace slag, vitreous calcium aluminosilicate
(VCAS), Class C fly ash, and concrete kiln dust.
7. The GUHPC mix of claim 1, wherein the binder comprises reactive
aluminosilicate and reactive alkali-earth aluminosilicate.
8. The GUHPC mix of claim 7, wherein the mass of the reactive
aluminosilicate is up to about 10 times, preferably from about 0.2
to about 0.8 times the mass of the reactive alkali-earth
aluminosilicate.
9. The GUHPC mix of claim 7, wherein reactive aluminosilicate
comprises about 2 to 15 wt % of the GUHPC mix.
10. The GUHPC mix of claim 7, wherein the mass of the reactive
alkali-earth aluminosilicate is up to about 20 times, preferably
from about 2 to about 5 times the mass of the reactive
aluminosilicate.
11. The GUHPC mix of claim 7, wherein the reactive alkali-earth
aluminosilicate comprises about 8 to about 25 wt % of the GUHPC
mix.
12. The GUHPC mix of claim 1, further comprising one or more
filler, comprising up to about 35 wt %, preferably from about 2 to
about 25 wt % of the GUHPC mix.
13. The GUHPC mix of claim 12, wherein the one or more filler has a
particle size of between 1 and 75 .mu.m, and is selected from the
group consisting of crushed quartz, Class F fly ash, Class C fly
ash, zeolite, ground glass, metakaolin, ground granulated blast
furnace slag, ultrafine furnace slag, and ultrafine fly ash.
14. The GUHPC mix of claim 12, wherein the one or more filler has a
particle size of between about 0.05 and 1 .mu.m, and is selected
from the group consisting of silica fume, precipitated silica,
ultrafine calcium carbonate, micron alumina, and submicron
particles of metal oxides.
15. The GUHPC mix of claim 1, wherein the one or more aggregate has
a particle size between about 0.075 and 10 mm, and comprises up to
about 75 wt %, preferably about 30 to 60 wt % of the GUHPC mix.
16. The GUHPC mix of claim 15, wherein the one or more aggregate
comprises one or more coarse aggregate having a particle size of
between about 0.075 and about 10 mm that is selected from the group
consisting of quartz sand, granite, basalt, gneiss, crushed
granulated blast furnace slag, limestone and calcined bauxite
sand.
17. The GUHPC mix of claim 1, wherein the one or more aggregate
comprises one or more fine aggregate with a particle size of
between about 0.075 and 0.75 mm.
18. The GUHPC mix of claim 1, wherein the alkali activator solution
is about 10 to 40 wt %, more preferably about 15 to about 25 wt %,
of the GUHPC mix
19. The GUHPC mix of claim 1, wherein the metal hydroxide comprises
sodium hydroxide, potassium hydroxide, or both.
20. The GUHPC mix of claim 1, wherein the metal hydroxide comprises
about 2 to 10 wt % as M.sub.2O of the GUHPC mix.
21. The GUHPC mix of claim 1, wherein the metal silicate comprises
sodium silicate, potassium silicate, or both.
22. The GUHPC mix of claim 1, wherein the metal silicate comprises
about 2 to 10 wt % as SiO.sub.2 of the GUHPC mix.
23. The GUHPC mix of claim 1, wherein the alkali activator
comprises water at about 4 to 25 wt %, more preferably about 5 to
15 wt %, of the GUHPC mix.
24. The GUHPC mix of claim 1 further comprises one or more fiber,
comprising up to about 15 wt % of the GUHPC mix.
25. The GUHPC mix of claim 24, wherein the one or more fiber is
selected from the group consisting of organic fiber, glass fiber,
mineral fiber, basalt fiber, carbon fiber, nano fiber, and metal
fiber.
26. The GUHPC mix of claim 1, further comprising one or more
strength enhancer, comprising up to about 2 wt % of the GUHPC
mix.
27. The GUHPC mix of claim 26, wherein the one or more strength
enhancer is selected from the group consisting of aluminum
hydroxide, alkali carbonate, alkali phosphate, alkali sulfate,
alkali oxalate, and alkali fluoride.
28. The GUHPC mix of claim 1, further comprising superplasticizer
solids, comprising up to about 5 wt % of the GUHPC mix.
29. The GUHPC mix of claim 1, further comprising a set retarder,
comprising up to about 5 wt % of the GUHPC mix
30. The GUHPC mix of claim 1, wherein the packing density of all
solid components in the GUHPC mix is at least 0.5 (v/v), preferably
at least 0.6 (v/v), more preferably at least 0.7 (v/v).
31. The GUHPC mix of claim 1, wherein the GUHPC mix results in a
product with a 28-day compressive strength of at least about 10,000
psi.
32. The GUHPC mix of claim 1, wherein the GUHPC mix results in a
product with a 28-day compressive strength of at least about 20,000
psi.
33. The GUHPC mix of claim 1, wherein the GUHPC mix results in a
product with a 28-day compressive strength of at least about 25,000
psi.
34. The GUHPC mix of claim 1, wherein the GUHPC mix results in a
product with a setting time of about 30 minutes to 3 hours.
35. The GUHPC mix of claim 1, wherein the GUHPC mix results in a
product with a setting temperature between about 0.degree. C. and
150.degree. C.
36. A method of making a geopolymeric composite ultra high
performance concrete (GUHPC) product, comprising: a. mixing a GUHPC
dry mix with an activator solution to form a GUHPC paste; and b.
setting and curing the GUHPC paste to form a GUHPC product; wherein
said GUHPC dry mix comprises a binder at about 10 to 50 wt %, the
binder comprising one or more selected from the group consisting of
reactive aluminosilicate and reactive alkali-earth aluminosilicate,
and the activator solution comprises an aqueous solution of metal
hydroxide and metal silicate; the dry mix further comprises one or
more selected from the group consisting of aggregate, filler, and
fiber.
37. The method of claim 36, wherein the GUHPC paste further
comprises one or more selected from the group consisting of
strength enhancer, superplasticizer solids and set retarder.
38. The method of claim 36, wherein the activator solution has a
molar concentration of alkali hydroxide from about 5 to about 15,
preferably from about 7 to about 12.
39. A method of making a geopolymeric composite ultra high
performance concrete (GUHPC) product from a GUHPC mix, said method
comprising mixing the components of a GUHPC mix in an intensive
mixer until the mixture progresses through a granule like
consistency and develops into a smooth pourable paste with
continued mixing; wherein the GUHPC mix comprises an activator
solution and a binder; the activator solution comprising an aqueous
solution of metal hydroxide and metal silicate, the binder
comprising one or more selected from the group consisting of
reactive aluminosilicate and reactive alkali-earth
aluminosilicate.
40. The method of claim 39, wherein the GUHPC mix has a
water-to-geopolymer solids mass ratio (W/C) of between about 0.12
and about 0.65, preferably between about 0.20 and about 0.50, more
preferably between about 0.30 and about 0.45.
Description
CROSS REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This application claims priority to U.S. Application Ser.
No. 61/457,052, filed Dec. 17, 2010, incorporated herein by
reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to geopolymer composite
binders for ultra high performance concrete and methods of making
and using thereof.
BACKGROUND OF THE INVENTION
[0003] The following description of the background of the invention
is provided simply as an aid in understanding the invention and is
not admitted to describe or constitute prior art to the
invention.
[0004] During the last ten years, considerable advances have been
made in the development of high-performance, or more recently
ultra-high-performance, concretes with Portland cement. Ultra high
performance concrete (UHPC) represents a major development step
over high performance concrete (HPC), through the achievement of
very high strength and very low permeability. Typically, UHPC's
compressive strength varies from about 120 to 400 MPa, its tensile
strength varies from about 10 to 30 MPa, and its modulus of
elasticity is in the range of about 60 to 100 GPa.
[0005] UHPC benefits from being a "minimum defect" material--a
material with a minimum amount of defects such as micro-cracks and
interconnected pores with a maximum packing density. One approach
to minimizing defects is the Macro Defect Free (MDF) approach,
which uses polymers to fill in pores in the concrete matrix. The
process required to manufacture MDF concretes is very demanding,
and includes laminating and pressing. MDF concretes are susceptible
to water damage, have a large amount of creep, and are very
fragile. Another approach to minimizing defects is the Densified
with Small Particles (DSP) approach, which uses high amounts of
superplasticizer and silica fume in the concrete mix. DSP concretes
must either use extremely hard coarse aggregates or eliminate them
entirely in order to prevent the aggregates from being the weakest
component of the mix. DSP concretes do not require the extreme
manufacturing conditions that MDF concretes do, but DSP concretes
have a much lower tensile strength. Addition of steel fibers has
been considered to improve the ductility of DSP concrete.
[0006] Principles employed in conventional UHPC include improved
homogeneity through elimination of coarse aggregate; enhanced
packing density by optimization of the granular mixture through a
wide distribution of powder size classes; improved matrix
properties by the addition of a pozzolanic admixture such as silica
fume; improved matrix properties by reducing water/binder ratio;
enhanced ductility through inclusion of small steel fibers; and
enhanced mechanical performance through post-set heat-treatment
(90-150.degree. C.) to transform amorphous hydrates into
crystalline products, making an improved microstructure
(tobermorite, xonotlite) possible.
[0007] Several types of UHPC have been developed in different
countries and by different manufacturers. The main difference
between the various types of UHPC is the type and amount of fibers
used. The four main types of UHPC are Ceracem/BSI, compact
reinforced composites (CRC), multi-scale cement composite (MSCC),
and reactive powder concrete (RPC). RPC is the most commonly
available UHPC and one such product is currently marketed under the
name Ductual.RTM. by Lafarge, Bouygues and Rhodia.
[0008] RPC concrete mixes usually contain fine sand (150-600
.mu.m), Portland cement (<100 .mu.m), silica fume (0.1-0.2
.mu.m), crushed quartz (5-30 .mu.m), short fibers,
superplasticizer, and water. A typical RPC concrete mix has about
38.8% sand, 22.7% Portland cement, 10.6% silica fume, 8.1% crushed
quartz, 2.0% steel fiber or organic fiber, 1.4% superplasticizer,
and 16.5% water (all in volume percent).
[0009] Portland cement is the primary binder used in conventional
UHPC, but at a much higher proportion as compared to ordinary
concrete or HPC. Cement with high proportions of tricalcium
aluminate (C.sub.3A) and tricalcium silicate (C.sub.3S), and a
lower Blaine fineness are desirable for conventional UHPC, as the
C.sub.3A and C.sub.3S contribute to high early strength and the
lower Blaine fineness reduces the water demand. The addition of
silica fume fulfills several roles including particle packing,
increasing flowability due to spherical nature, and pozzolanic
reactivity (reaction with the weaker hydration product calcium
hydroxide) leading to the production of additional calcium
silicates. Quartz sand with a maximum diameter of about 600 .mu.m
is the largest constituent aside from the steel fibers. Both the
ground quartz (about 10 .mu.m) and quartz sand contribute to the
optimized packing By reducing the amount of water necessary to
produce a fluid mix, and therefore permeability, the
polycarboxylate superplasticizer also contributes to improving
workability and durability. Finally, the addition of steel fibers
aids in preventing the propagation of microcracks and macrocracks
and thereby limits crack width and permeability.
[0010] Despite performance advantages offered by UHPC, deployment
has been slow. There are several possible reasons for this,
including lack of a clear financial benefit to manufacturers. As
would be expected, the costs of fabricating UHPC components are
significantly higher than the costs of manufacturing conventional
concrete components. Additionally, the higher cost of constituent
materials in UHPC necessarily means that UHPC has a higher per-unit
volume cost than conventional and high-performance concretes. Much
of the cost of UHPC comes from its steel fiber, superplasticizer,
and high purity fumed silica. Ultra-high performance fiber
reinforced concrete is generally cured with heat and/or pressure to
enhance its properties and to accelerate the hydration reaction of
the binder, which also increases manufacturing cost.
[0011] The present invention relates to use of geopolymer composite
(GC) binders, rather than Portland cement, for Ultra High
Performance Concrete (GUHPC) applications.
SUMMARY OF THE INVENTION
[0012] One aspect of the present invention provides geopolymeric
composite ultra high performance concrete (GUHPC) mix, comprising:
(a) a binder comprising one or more selected from the group
consisting of reactive aluminosilicate and reactive alkali-earth
aluminosilicate; and (b) an alkali activator comprising an aqueous
solution of metal hydroxide and metal silicate, and (c) one or more
aggregate.
[0013] In some embodiments, the binder comprises about 10 to 50 wt
% of the GUHPC mix. In some embodiments, the binder comprises one
or more reactive aluminosilicate comprising about 0 to 30 wt % of
the GUHPC mix. In some related embodiments, the one or more
reactive aluminosilicate is selected from the group consisting of
metakaolin, reactive aluminosilicate glasses, and ultrafine Class F
fly ash. In some embodiments, the one or more reactive
aluminosilicate comprises metakaolin.
[0014] In some embodiments, the binder comprises one or more
reactive alkali-earth aluminosilicate, comprising about 2 to 40 wt
% of the GUHPC mix. In some related embodiments, the one or more
reactive alkali-earth aluminosilicate is selected from the group
consisting of granulated blast furnace slag, vitreous calcium
aluminosilicate (VCAS), Class C fly ash, and concrete kiln dust. In
some related embodiments, the one or more reactive alkali-earth
aluminosilicate comprises ground granulated blast furnace slag.
[0015] In some embodiments, the binder comprises reactive
aluminosilicate and reactive alkali-earth aluminosilicate. In some
related embodiments, the mass of the reactive aluminosilicate is up
to about 10 times, preferably up to about 1.5 times, preferably
from about 0.2 to about 0.8 times, the mass of the reactive
alkali-earth aluminosilicate. In some relate embodiments, the mass
of the reactive alkali-earth aluminosilicate is up to about 20
times, preferably from about 2 to about 5 times, the mass of the
reactive aluminosilicate. In some related embodiments, the one or
more reactive aluminosilicate comprises about 2 to about 15 wt % of
the GUHPC mix. In some related embodiments, the reactive
alkali-earth aluminosilicate comprises about 8 to about 25 wt % of
the GUHPC mix.
[0016] In some embodiments, the GUHPC mix further comprises one or
more filler, comprising up to about 35 wt %, preferably from about
2 to about 25 wt %, of the GUHPC mix. In some related embodiments,
the one or more filler comprise one or more reactive filler. In
some related embodiments, the one or more filler is selected from
the group consisting of crushed quartz powder, Class F fly ash,
Class C fly ash, zeolite, ground waste glass, silica fume,
ultrafine fly ash, precipitated silica, and micron alumina. In some
related embodiments, the one or more filler comprises silica fume.
In some related embodiments, the one or more filler comprises
crushed quartz powder and silica fume. In some related embodiments,
the one or more filler comprises Class C fly ash. In some related
embodiments, the one or more filler comprises Class F fly ash. In
some related embodiments, the one or more filler comprises silica
fume and Class F fly ash. In some related embodiments, the one or
more filler comprises silica fume and Class C fly ash. In some
related embodiments, the one or more filler has a particle size of
between 1 and 75 .mu.m, and is selected from the group consisting
of crushed quartz, Class F fly ash, Class C fly ash, zeolite,
ground glass, metakaolin, ground granulated blast furnace slag,
ultrafine furnace slag, and ultrafine fly ash. In some related
embodiments, the one or more filler has a particle size of between
about 0.05 and 1 .mu.m, and is selected from the group consisting
of silica fume, precipitated silica, ultrafine calcium carbonate,
micron alumina, and submicron particles of metal oxides.
[0017] In some embodiments, the one or more aggregate comprises
about 0 to 75 wt %, preferably about 30 to 60 wt % of the GUHPC
mix. In some related embodiments, the one or more aggregate
comprises particulate matter with a particle size of about 0.075 to
10 mm. In some related embodiments, the one or more aggregate
comprises one or more coarse aggregate having a particle size of
between about 0.075 and about 10 mm that is selected from the group
consisting of quartz sand, granite, basalt, gneiss, crushed
granulated blast furnace slag, limestone and calcined bauxite sand.
In some related embodiments, the one or more aggregate comprises a
fine aggregate with a particle size of between about 0.075 and 0.75
mm. In some related embodiments, the one or more aggregate
comprises masonry sand, fine river sand, or both.
[0018] In some embodiments, the alkali activator solution comprises
about 10 to 40 wt %, more preferably about 15 to about 25 wt %, of
the GUHPC mix. In some embodiments, the metal hydroxide comprises
about 2 to 15 wt % as M.sub.2O of the GUHPC mix. In some
embodiments, the metal hydroxide comprises sodium hydroxide,
potassium hydroxide, or both. In some embodiments, the metal
hydroxide comprises about 2 to 10 wt % as M.sub.2O of the GUHPC
mix. In some embodiments, water from the alkali activator solution
comprises about 4 to 25 wt %, more preferably about 5 to 15 wt %,
of the GUHPC mix.
[0019] In some embodiments, the metal silicate comprises about 2 to
10 wt % as SiO.sub.2 of the GUHPC mix. In some embodiments, the
metal silicate comprises an alkali metal silicate or an alkali
earth metal silicate. In some embodiments, the metal silicate
comprises sodium silicate, potassium silicate, or both.
[0020] In some embodiments, the GUHPC mix further comprises one or
more fiber, comprising about 0 to 15 wt % of the GUHPC mix. In some
related embodiments, the one or more fiber comprises one or more
fiber selected from the group consisting of organic fiber, glass
fiber, carbon fiber, nano fiber, and metal fiber. In some related
embodiments, the one or more fiber comprises steel fiber.
[0021] In some embodiments, the GUHPC mix further comprises one or
more strength enhancer, comprising up to about 2 wt % of the GUHPC
mix. In some related embodiments, the one or more strength enhancer
is selected from the group consisting of aluminum hydroxide, alkali
carbonate, alkali phosphate, alkali sulfate, alkali oxalate, and
alkali fluoride. In some related embodiments, the one or more
strength enhancer is selected from the group consisting of aluminum
hydroxide, sodium carbonate, sodium phosphate, sodium sulfate,
sodium oxalate, and sodium fluoride.
[0022] In some embodiments, the GUHPC mix further comprises
superplasticizer solids, comprising up to about 5 wt % of the GUHPC
mix.
[0023] In some embodiments, the GUHPC mix further comprises a set
retarder. In some related embodiments, the set retarder comprises
up to about 5 wt % of the GUHPC mix.
[0024] In some embodiments, the packing density of all solid
components in the GUHPC mix is at least 0.5 (v/v), such as at least
0.6 (v/v); such as at least 0.75 (v/v).
[0025] In some embodiments, the GUHPC mix results in a GUHPC
product with a 28-day compressive strength of at least about 10,000
psi, such as at least about 20,000 psi, such as at least about
25,000 psi.
[0026] In some embodiments, the GUHPC mix results in a GUHPC
product with a setting time of about 30 minutes to 3 hours.
[0027] In some embodiments, the GUHPC mix results in a GUHPC
product with a setting temperature between about 0 and 150.degree.
C., such as between about 20 and 90.degree. C.
[0028] In another aspect, methods of making geopolymeric composite
ultra high performance concrete (GUHPC) products from GUHPC mixes
described herein are provided. In some methods, a GUHPC dry mix is
mixed with an activator solution to form a GUHPC paste; which is
set and cured to form a GUHPC product. In these methods, the GUHPC
dry mix comprises a binder at about 10 to 50 wt %, the binder
comprising one or more selected from the group consisting of
reactive aluminosilicate and reactive alkali-earth aluminosilicate,
and the activator solution comprises an aqueous solution of metal
hydroxide and metal silicate. The GUHPC dry mix further comprises
one or more selected from the group consisting of aggregate,
filler, and fiber.
[0029] In some embodiments, the alkali hydroxide comprises one or
more of sodium hydroxide and potassium hydroxide or both.
[0030] In some embodiments, the mixing is conducted with an
intensive mixer.
[0031] In some embodiments, the GUHPC paste further comprises one
or more selected from the group consisting of strength enhancer,
superplasticizer solids and set retarder.
[0032] In some embodiments, the GUHPC product comprises one or more
fibers, which are added to the GUHPC pourable paste prior to
setting.
[0033] In some embodiments, the GUHPC product comprises one or more
strength enhancers, which are added to the aqueous solution of one
or more alkali activators prior to mixing with the GUHPC dry
mix.
[0034] In some embodiments, the activator solution has a molar
concentration of alkali hydroxide from about 5 to about 15,
preferably from about 7 to about 12.
[0035] In another aspect, methods of making a geopolymeric
composite ultra high performance concrete (GUHPC) product from a
GUHPC mix are provided where the components of a GUHPC mix are
mixed in an intensive mixer until the mixture progresses through a
granule like consistency and develops into a smooth pourable paste
with continued mixing. In these embodiments, the GUHPC mix
comprises an activator solution and a binder; the activator
solution comprising an aqueous solution of metal hydroxide and
metal silicate, the binder comprising one or more selected from the
group consisting of reactive aluminosilicate and reactive
alkali-earth aluminosilicate. In some embodiments, the GUHPC mix
has a water to geopolymer solids ratio (W/C) of between about 0.12
to 0.65; such as between about 0.2 to 0.5; such as between about
0.3 to 0.45.
[0036] The term "about" as used herein in reference to quantitative
measurements not including the measurement of the mass of an ion,
refers to the indicated value plus or minus 10%. Unless otherwise
specified, "a" or "an" means "one or more."
[0037] The summary of the invention described above is non-limiting
and other features and advantages of the invention will be apparent
from the following detailed description of the invention, and from
the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] FIG. 1 shows a plot of the compressive strength of various
GUHPC samples as a function of curing time. Details are discussed
in Example 14.
DETAILED DESCRIPTION OF THE INVENTION
[0039] One aspect described herein provides a geopolymer composite
ultra high performance concrete (GUHPC) mix composition. At a
minimum, a GUHPC mix includes: i) a binder comprising at least one
reactive amorphous aluminosilicate material, such as metakaolin,
and/or at least one reactive amorphous alkali-earth
aluminosilicate, such as ground granulated blast furnace slag; and
ii) an aqueous solution comprising at least one alkali
activator.
[0040] In some embodiments, additional constituents may be included
in the GUHPC mix. For example, (reactive and/or nonreactive) filler
with a particle size up to about 75 .mu.m, and/or aggregate, such
as fine masonry sand of particle size between about 75 to 750
.mu.m, such as about 250 .mu.m may also be included in the mix.
Additionally, constituents such as fibers, strength enhancers,
superplasticizer, and set retarders may also be included to affect
GUHPC performance.
[0041] To form a GUHPC, the dry constituents of the GUHPC mix
composition (binder, and filler and aggregate, if present) are
combined with an alkali activator solution. The constituents are
mixed to form a pourable paste, which sets to a GUHPC product as
the constituents form geopolymers. Geopolymers consist of silicon
and aluminum atoms bonded via oxygen atoms into a polymer network.
The process of forming geopolymers involves
dissolution/condensation/poly-condensation/polymerization
reactions, which begin as soon as certain reactive aluminosilicate
materials are exposed to an alkaline solution. Using certain
aluminosilicate materials that are highly reactive in alkaline
solutions and optimizing compositions and properties of alkaline
activator solutions allow one to produce very dense, durable
geopolymer matrices of extremely high mechanical strength.
[0042] By employing certain principles true for conventional UHPC
such as increased homogeneity by excluding coarse aggregates and an
increased aggregate packing by selecting particle size
distributions, a UHPC with geopolymer composite can be obtained
with compressive strength above 20000 psi. Unlike conventional
UHPC, use of heat treatment and addition of large amount of
superplasticizer are not necessary to achieve ultra high
performance. With an intensive mixer, water to geopolymer solids
ratios (W/C) can be decreased without significant doping with a
superplasticizer. In contrast, conventional UHPC uses large
quantities of superplasticizer to lower W/C ratios. In addition,
GUHPC has no Portland cement at all, uses mostly industrial waste,
and does not emit carbon dioxide in production. Thus, GUHPC is much
less expensive than conventional UHPC, while being a much greener
concrete. GUHPC also exhibits much greater heat-, fire-, impact-,
and acid-resistance than conventional UHPC.
[0043] Principles of GUHPC
[0044] It is well known that performance of geopolymer products
depend on both the reactivity and mass of gel formed. The Inventors
have found that alkali activation of reactive aluminosilicate
materials, such as metakaolin, generates large amounts of alkali
aluminosilicate gel (AAS gel).
[0045] Alkali activation of reactive alkali-earth aluminosilicate
materials, such as ground granulated blast furnace slag, vitreous
calcium aluminosilicate, or Class C fly ash, also produces abundant
calcium silicate hydrate (CSH) gel and/or related gels and/or
calcium aluminosilicate hydrate (CASH) gel, in addition to AAS
gel.
[0046] Alkali activation of reactive aluminosilicate and reactive
alkali-earth aluminosilicate are very quick with reactions
completed in a few hours (e.g., metakaolin) to a few days (e.g.,
ground granulated blast furnace slag, Class C fly ash) at room
temperature. Increasing temperature significantly enhances alkali
activation and hardening processes.
[0047] The Inventors have also found that a geopolymer composite
made of two or more reactive aluminosilicate materials results in a
hybrid matrix of AAS, CSH and/or related gels, and/or calcium
aluminosilicate hydrate (CASH) with a higher rate of strength gain
as well as a higher final strength of the geopolymer product.
Optimization of the AAS gel to CSH gel ratio in a geopolymer
composite matrix can yield maximum strength performance.
[0048] Basic principles for conventional UHPC are also true for
GUHPC, such as increased homogeneity by excluding coarse aggregates
and an increased aggregate packing by selecting particle size
distributions. In some embodiments, readily available fine river
sand or masonry sand (e.g., particle size about 75 to 750 .mu.m)
may be used as fine aggregate in order to reduce production cost.
In other embodiments, other sands, such as masonry sand, may be
used as aggregate. In certain embodiments, one or more fine and/or
ultrafine reactive fillers may be used having a particle size of
between about 3 to 75 .mu.m, thereby eliminating the crushed quartz
powder (5 to 30 .mu.m) found in typical reactive powder concrete
(RPC) mixtures. In some embodiments, submicron fillers with a
particle size ranging from about 0.05 to about 1 .mu.m may be used.
While the reactive fillers (fine, ultrafine, and submicron) act as
filling the voids in the next larger granular class in the mix, the
fillers also react with alkali sources (pozzolanic reaction) with
increasing curing time and produce additional AAS gel to support
long-term strength growth.
[0049] In some embodiments, the inclusion of aggregate and filler
materials in the GUHPC mix results in a packing density of all
solid additives (i.e., binder materials, aggregate (if present),
and filler (if present)) of at least 0.5 (v/v); such as at least
0.6 (v/v); such as 0.75 (v/v).
[0050] Water/Geopolymer solids ratio (W/C) has been used as an
indicator of concrete strength. The term geopolymer solids is
defined as the sum of binder constituents and dissolved silica and
alkali oxides in the activator solution. W/C affects porosity and
pore size distributions of geopolymer matrix. A smaller W/C ratio
usually results in a geopolymer gel with smaller pores (e.g., about
20 to 100 nm in size) and in turn higher compressive strength.
[0051] The inventors have determined that a GUHPC mix with optimal
or near optimal W/C exhibits a characteristic progression through
various stages under continued intensive mixing. With an optimal or
near optimal W/C ratio, one observes that the GUHPC mix initially
develops a sand or granule like consistency, which suggests an
insufficient amount of water is present. However, continued mixing,
without adding additional water, results in the sand or granule
like mixture forming a mixture with dough like consistency, and
finally a homogeneous, workable, flowable paste that is ready for
pouring. The inventors have further determined that GUHPC products
made from GUHPC mixes which exhibit this sequence are exceptionally
strong, with compressive strength in excess of 20,000 psi cured for
28 days at room temperature.
[0052] The inventors have determined that the preferred W/C range
for GUHPC mixes as described herein is within the range of about
0.12 to about 0.65; such as about 0.2 to about 0.5; such as about
0.3 to about 0.45.
[0053] The following is a more detailed description of various
constituents that may be present in certain GUHPC mixes of the
present invention. The constituents from which the GUHPC is made
include at least a binder comprising at least one reactive
aluminosilicate and/or at least one reactive alkali-earth
aluminosilicate, and an aqueous activator solution. Additional
components included in certain embodiments discussed herein include
filler, aggregate, fiber, strength enhancers, superplasticizer, set
retarder, and any combination thereof. This list is not intended to
be exhaustive, and as understood by one of skill in the art, other
components may also be included.
[0054] Reactive Aluminosilicate Materials
[0055] The first constituent in a GUHPC mix is the binder, which
comprises reactive aluminosilicate and/or reactive alkali earth
aluminosilicate. Examples of reactive aluminosilicate containing
materials suitable for use in the present invention include
Metakaolin (MK), Ground Granulated Blast Furnace Slag (GGBFS),
Vitreous Calcium Aluminosilicate (VCAS), Class F fly ash (FFA), and
Class C fly ash (CFA).
[0056] Metakaolin is one of the most reactive aluminosilicate
pozzolans, a finely-divided material (e.g., within the range of
about 0.1 to 20 microns) that reacts with slaked lime at ordinary
temperature and in the presence of moisture to form strong
slow-hardening cement. Metakaolin is formed by calcining purified
kaolinite, generally between 650-700.degree. C., in a rotary kiln.
Alkali activation of metakaolin can be completed within several
hours.
[0057] Depending on the chemical composition and method of
production, ground granulated blast furnace slag (GGBFS) is a
glassy granular material that varies from a coarse, popcorn-like
friable structure with particle size greater than about 4.75 mm in
diameter, to dense, sand-size grains. Grinding reduces the particle
size to cement fineness, allowing its use as a supplementary
cementitious material in Portland cement-based concrete. Typical
ground granulated blast furnace slag includes about 27-38%
SiO.sub.2, 7-12% Al.sub.2O.sub.3, 34-43% CaO, 7-15% MgO, 0.2-1.6%
Fe.sub.2O.sub.3, 0.15-0.76% MnO and 1.0-1.9% others by weight.
Because GGBFS is almost 100% glassy (or "amorphous"), it is
generally more reactive than most fly ashes. GGBFS produces a
higher proportion of the strength-enhancing calcium silicate
hydrate (CSH) than Portland cement, thereby resulting in higher
ultimate strength than concrete made with Portland cement.
[0058] Fly ash is a fine powder byproduct formed from the
combustion of coal. Electric power plant utility furnaces burning
pulverized coal produce most of the commercially available fly
ashes. These fly ashes consist mainly of glassy substantially
spherical particles, as well as hematite, magnetite, unburned
carbon, and some crystalline phases formed during cooling. American
Society for Testing and Materials (ASTM) C618 standard recognizes
two major classes of fly ashes for use in concrete: Class C and
Class F. In the ASTM C618 standard, one major specification
difference between the Class F fly ash and Class C fly ash is the
lower limit of (SiO.sub.2+Al.sub.2O.sub.3+Fe.sub.2O.sub.3) in the
composition. The lower limit of
(SiO.sub.2+Al.sub.2O.sub.3+Fe.sub.2O.sub.3) for Class F fly ash is
70% and that for Class C fly ash it is 50%. Accordingly, Class F
fly ashes generally have a calcium oxide content of about 15 wt %
or less, whereas Class C fly ashes generally have a higher calcium
oxide content (e.g., higher than 15 wt %, such as about 20 to 40 wt
%). High calcium oxide content makes Class C fly ashes possess
cementitious properties leading to the formation of calcium
silicate and calcium aluminate hydrates when mixed with water.
[0059] Any reactive aluminosilicate known in the art may be used,
but metakaolin is the most favorable as it is readily available and
has small particle size, such as from about 0.5 to 20 .mu.m. The
rates of metakaolin dissolution and polymerization in an alkaline
solution can be very high (i.e., from minutes to hours), and the
water expelled during geopolymerization can help improve the
workability of the GUHPC paste and enhance the
alkali-activation/hydration of a reactive alkali-earth
aluminosilicate.
[0060] Certain synthetic pozzolanic materials are even more
reactive than metakaolin. For example, the inventors have
synthesized reactive aluminosilicate glasses with chemical
compositions analogous to that in Class F fly ash at temperatures
between about 1400.degree. C. and 1500.degree. C. Raw materials
useful for synthesis of reactive aluminosilicate glasses include
Class F fly ash with addition of small amount of flux components
(such as soda) or other individual chemicals. Prior to use in GUHPC
mixes, synthetic glass may be ground passing 325 mesh. Alkali
activation of the synthetic glass powders usually yields
compressive strength over 20,000 psi after curing for 28 days.
[0061] In general, Class F fly ash is less reactive than
metakaolin, though Class F fly ash is essentially an
aluminosilicate glass. The reactivity of Class F fly ash depends on
the amount of the amorphous phase contained therein, on the
particle size of the spherical fly ash solid, and on curing
temperature. According to the Inventors' measurements, the
activation energy of hydration can be as high as about 100 kJ/mol
for conventional Class F fly ash based geopolymer in the
temperature range of about 20 to 75.degree. C. By comparison,
activation energies of hydration of Portland cements and furnace
slag range from about 20 to 50 kJ/mol. Without post-set heat
treatment, as usually applied to manufacture conventional UHPC,
conventional Class F fly ash may not be a preferred reactive
aluminosilicate in a GUHPC depending on particle size.
[0062] To be used as a reactive aluminosilicate in a GUHPC mix
cured at room temperature, the Class F fly ash preferably has a
particle size smaller than about 15 .mu.m, as well as low amounts
of unburnt carbon, such as less than about 1 wt %. Such Class F fly
ashes preferably have a mean particle size of about 3 .mu.m, and
may be processed from raw fly ash by mechanical removal of coarser
particles. Ultrafine fly ash can also be produced by a grinding
process. Fly ashes with a median particle size in the 6 to 10 .mu.m
range may be generated in this way.
[0063] Reactive Alkali-Earth Aluminosilicate
[0064] As already discussed, the binder comprises reactive
aluminosilicate and/or reactive alkali earth aluminosilicate.
Examples of reactive alkali-earth aluminosilicate materials are
ground granulated blast furnace slag (GGBFS), vitreous calcium
aluminosilicate (VCAS), Class C fly ash (CFA), and cement kiln dust
(CKD).
[0065] GGBFS is the most favorable reactive alkali-earth
aluminosilicate due to its high reactivity in alkaline solution and
its low cost. Although all three grades of furnace slag (i.e. 80,
100 and 120 by ASTM C989-92) are suitable for a GUHPC mix, furnace
slag grade 120 is preferred because it exhibits higher reactivity
in alkaline solution. Furthermore, ultrafine GGBFS is even more
reactive compared to furnace slag grade 120. For example
MC-500.RTM. Microfine.RTM. Cement (de neef Construction Chemicals)
is an ultrafine furnace slag with particle sizes less than about 10
.mu.m and specific surface area of about 800 m.sup.2/kg that is
more reactive than furnace slag grade 120.
[0066] VCAS is a waste product of fiberglass production. In a
representative glass fiber manufacturing facility, typically about
10-20 wt % of the processed glass material is not converted to
final product and is rejected as by-product or waste VCAS and sent
for disposal to a landfill. VCAS is 100% amorphous and its
composition is very consistent, mainly including about 50-55 wt %
SiO.sub.2, 15-20 wt % Al.sub.2O.sub.3, and 20-25 wt % CaO. Ground
VCAS exhibits pozzolanic activity comparable to silica fume and
metakaolin when tested in accordance with ASTM C618 and C1240.
Therefore, it can be a very reactive alkali-earth aluminosilicate
by forming additional cementitious compounds such as CSH and CASH
gels.
[0067] CKD is a by-product of the manufacture of Portland cement,
and therefore an industrial waste. Over 30 million tons of CKD are
produced worldwide annually, with significant amounts put into land
fills. Typical CKD contains about 38-64 wt % CaO, 9-16 wt %
SiO.sub.2, 2.6-6.0 wt % Al.sub.2O.sub.3, 1.0-4.0 wt %
Fe.sub.2O.sub.3, 0.0-3.2 wt % MgO, 2.4-13 wt % K.sub.2O, 0.0-2.0 wt
% Na.sub.2O.1.6-18 wt % SO.sub.3, 0.0-5.3 wt % Cl.sup.-, and 5.0-25
wt % LOI. CKD is generally a very fine powder (e.g., about
4600-14000 cm.sup.2/g specific surface area) and is a good reactive
alkali-earth aluminosilicate. When CKD is used in a GUHPC
formulation, elevated concentrations of the alkali oxides contained
in it enhance geopolymerization. Additional formation of CSH gel,
ettringite (3CaO.Al.sub.2O.sub.3.3CaSO.sub.4.32H.sub.2O), and/or
syngenite (a mixed alkali-calcium sulfate) can help develop early
strength of GUHPC.
[0068] The concrete composition comprises about 2 to 40 wt %
reactive alkali earth aluminosilicate, and preferably about 8 to 25
wt %. The concrete composition comprises up to 30 wt % reactive
aluminosilicate. The binder materials comprises reactive
alkali-earth aluminosilicate and reactive aluminosilicate, which
contribute up to about 50 wt %, such as about 20 to 40 wt %, such
as about 15 to 30 wt %, of a GUHPC mix.
[0069] In the binder, In the binder, a mass ratio of reactive
aluminosilicate to reactive alkali earth aluminosilicate ranges
from about 0.0 to about 10; a mass ratio of between about 0.2 and
about 0.8 is preferred.
[0070] In the binder, a mass ratio of reactive alkali earth
aluminosilicate to reactive aluminosilicate of between about 0.0 to
20 is preferred; such as between about 1 to 10; such as between
about 2 to 5.
[0071] Activator Solution
[0072] The second critical constituent in a GUHPC mix is the
activator solution. In addition to the above described binder, an
alkaline activation solution ("activator solution") must be added
to a GUHPC dry constituent mixture to form a complete GUHPC mix.
The activator is in effect a solution of one or more metal
hydroxides and one or more metal silicates.
[0073] In one embodiment, the one or more metal hydroxides comprise
one or more alkali metal hydroxides, such as sodium hydroxide,
potassium hydroxide, or both.
[0074] The one or more metal silicates may comprise one or more
alkali metal silicate and/or one or more alkaline earth metal
silicate. Alkali metal silicates, particularly a mixed solution of
potassium and sodium silicates, are desirable.
[0075] Silica fume or microsilica is composed of very small (e.g.,
about 0.1 .mu.m in size) glassy silica particles (SiO.sub.2) which
are substantially spherical with a specific surface area on the
order of 20 m.sup.2/g. Silica fume is extremely reactive in
alkaline solution. An activator solution is prepared by dissolving
silica fume in alkali hydroxide solution. In some embodiments of
the present invention, silica fume is also applied as a reactive
filer. Unlike conventional Portland cement based UHPC, GUHPC is
tolerant to unburned carbon present in industrial waste silica fume
up to about 5 wt %, such as in silica fume from the production of
silicon and ferrosilicon alloys. GUHPC made from such industrial
waste silica fume may appear grey or darker in color. However,
GUHPC comprising white silica fume, such as from the zirconium
industry, contain much less unburnt carbon and appear white in
color. Thus, certain colorants or pigments may be added to GUHPC
made from white silica fume to achieve a variety of colors in the
final product.
[0076] In some embodiments, silica fume may be used to make the
activator solution by dissolving it in an alkali hydroxide
solution, together with strength enhancers (if present). In other
embodiments, alkali silicate glass powders may be dissolved in
alkali hydroxide solution to prepare an activator solution.
Elevated temperature may help increase rate of dissolution for
alkali silicate glass powders. Examples of commercially available
soluble alkali silicate glasses include SS.RTM. sodium silicate and
Kasolv.RTM. potassium silicate from PQ Corporation. In other
embodiments, commercially available alkali silicate solutions may
be used to prepare activator solutions. Examples of such alkali
silicate solutions include Ru.TM. sodium silicate solution and
KASIL.RTM. 6 potassium silicate solution from PQ Corporation. When
these commercial soluble alkali silicate materials are used to
prepare activator solutions, the GUHPC products are usually light
in color. If desired, certain pigments can be added to create
various finishing colors.
[0077] The activator solution contributes to the GUHPC mix as
follows: metal hydroxide as M.sub.2O (M=Na, K, or both) at about 2
to 15 wt %, silicate as SiO.sub.2 at about 2 to 15 wt %, and water
at 4 to 25 wt %.
[0078] Preferably, metal hydroxide is added as hydroxides of
sodium, potassium, or both; more preferably, about 2 to 10 wt %,
Na.sub.2O (added as NaOH), K.sub.2O (added as KOH), or both; more
preferably, about 2 to 8 wt %, Na.sub.2O (added as NaOH), K.sub.2O
(added as KOH), or both.
[0079] Preferably, SiO.sub.2 is added as silica fume. Preferably,
dissolved SiO.sub.2 is present in the GUHPC mix at about 2 to 10 wt
%, more preferably about 2 to 8 wt %
[0080] Preferably, water is present in the GUHPC mix at about 4 to
25 wt %; more preferably at about 7 to 15 wt %.
[0081] Filler
[0082] One optional constituent in a GUHPC mix is filler with a
particle size up to about 75 .mu.m. Two types of fillers can be
classified in terms of their particle sizes and reactivity in
alkaline solution. One type of filler comprises mainly reactive
submicron particles having a particle size of between about 0.05 to
1 .mu.m. Another type of filler comprises fine and ultrafine
particles having particle sizes of between about 1 to 75 .mu.m.
[0083] The combined filler may comprise up to about 35 wt % of a
GUHPC mix. Preferably, the combined filler comprises between about
2 and 35 wt %. More preferably, the combined filler comprises
between about 2 and 25 wt %.
[0084] Exemplary fine and ultrafine fillers include calcined
zeolites, Class F fly ash, Class C fly ash, coal gasification fly
ash, volcanic ash, and ground waste glass powder. In general, these
filler particles are also quite reactive upon exposure to an
alkaline solution. Fly ashes, including Class F and Class C fly
ashes, usually have a particle size between about 5 and 75 .mu.m.
Fly ashes with smaller particle sizes are preferred, such as
ultrafine fly ash (UFFA) with a mean particle size of about 1 to 10
.mu.m. UFFA is carefully processed my mechanically separating the
ultra fine fraction from the parent fly ash. Coal gasification fly
ash is discharged from coal gasification power stations, usually as
SiO.sub.2 rich substantially spherical particles having a maximum
particle size of about 5 to 10 .mu.m. Thus, coal gasification fly
ash is also suitable filler.
[0085] Class F fly ash is essentially an aluminosilicate glass that
is less reactive than metakaolin in alkaline solution. The
reactivity of Class F fly ash depends on the amount of the
amorphous phase contained therein, on the particle size of the fly
ash solid, and on curing temperature. According to the inventors'
measurements, the activation energy of hydration can be as high as
about 100 kJ/mol for Class F fly ash-based geopolymer in the
temperature range of about 20 to 75.degree. C. By comparison,
activation energies of hydration of Portland cements range from
about 20 to 50 kJ/mol. Class F fly ash may be used as filler as it
usually has a mean particle size of less than 75 microns, thus
allowing for the elimination of crushed quartz, one of the key
components in conventional UHPC. Class F fly ash with lower
unburned carbon (e.g., less than about 2 wt %) is preferred.
[0086] Metakaolin and ground granulated blast furnace slag may also
be included as reactive filler while they function as the binder as
well. Both of the materials have a particle size of between 0.5 and
75 .mu.m. They fill in voids to improve the packing density of the
GUHPC mix and react with the alkali silicate solution to form
additional AAS and CSH and/or CASH gels.
[0087] Examples of zeolites include Zeolite Type 5A, Zeolite Type
13.times., clinoptilolite, and phillipsite. The zeolite phases have
molar SiO.sub.2/Al.sub.2O.sub.3 ratios from about 2 to 7, which are
within the favorable range of formation of geopolymer compositions.
Heat treatment of zeolitic materials at temperatures between about
500 to 800.degree. C. renders them amorphous in structure and
reactive upon exposure to highly alkaline solution. Calcined
zeolitic materials typically have a particle size between about 0.5
and 10 .mu.m.
[0088] Exemplary submicron fillers useful in the present invention
include silica fume, precipitated silica, and micron sized alumina,
with silica fume being the most preferred. These submicron fillers
typically are extremely reactive upon exposure to alkaline
solution. Ultrafine calcium carbonate particles having a specific
surface area equal to or greater than about 10 m.sup.2/g can also
be used as submicron filler, though less reactive than silica fume.
Other materials having a particle size less than about 1 .mu.m may
also be used as submicron filler, though they may not necessarily
be reactive. Examples of such submicron particles include
Fe.sub.2O.sub.3, ZrO.sub.2, and SiC particles of appropriate
size.
[0089] As used in conventional UHPC, crushed quartz powder having a
particle size between about 1 and 75 .mu.m, and more preferably
between about 5 and 30 .mu.m, may be used to enhance optimization
of particle size distribution and is considered to be inert.
However, crushed quartz may become relatively reactive in GUHPC as
quartz particles with high surface area dissolve in highly alkaline
solutions with pH>14. Therefore, in GUHPC mixes of the present
invention, crushed quartz powder may be classified as weak reactive
filler.
[0090] In some embodiments, a single filler, preferably a single
reactive filler, is incorporated into a GUHPC mix. In some of these
embodiments, the single filler is silica fume. In these
embodiments, up to about 5 wt % silica fume is be incorporated into
GUHPC mixes. In other embodiments, multiple fillers, which may or
may not include one or more reactive fillers, are incorporated into
GUHPC mixes. For example, two fillers may be incorporated into a
GUHPC mix. In certain embodiments, silica fume and calcined Zeolite
type 5A may be incorporated into a GUHPC mix with combined amounts
of up to about 10 wt %. In other embodiments, silica fume and
crushed quartz powder may be incorporated into a GUHPC mix with the
amount of crushed quartz powder being up to about 25 wt %, such as
up to about 10 wt %, and the amount of silica fume up to about 8 wt
%, such as up to about 5 wt %. In yet other embodiments, silica
fume and Class C fly ash may be incorporated into a GUHPC mix with
the amount of silica fume up to about 8 wt %, such as up to about 5
wt %, and the amount of Class C fly ash up to about 25 wt %, such
as up to about 10 wt %. In yet other embodiments, silica fume and
Class F fly ash may be incorporated into a GUHPC mix with the
amount of silica fume up to about 8 wt % and the amount of Class F
fly ash up to about 25 wt %. In yet other embodiments, more than
two, such as three, four, or more, fillers may be incorporated into
a GUHPC mix.
[0091] In a GUHPC mix, fillers with different mean particle sizes
and reactivities may be added together to achieve the highest
packing density of a GUHPC mix and to enhance geopolymerization,
which may lead to improvement of product performance. Both silica
fume/fly ash (Class C and/or Class F) and silica fume/crushed
quartz powder are preferable examples of such combinations.
[0092] Aggregate
[0093] A second optional constituent in a GUHPC mix is an
aggregate. Aggregate confines the geopolymer matrix to add
strength, and may be fine or coarse, with fine aggregates
understood to have a particle size ranging from about 0.075 mm to 1
mm, such as from about 0.15 to 0.60 mm. If a fine aggregate is used
in the GUHPC mix, any fine aggregate known in the art may be used.
An exemplary fine aggregate is ordinary fine river sand, which may
be added to a GUHPC mix at up to about 75 wt %, such as from about
30 to 60 wt %, such as from about 40 to 60 wt %, such as from about
25 to 55 wt %, such as up to about 50 wt %, such as from about 10
to 30%, such as from about 15 to 25 wt %.
[0094] Optionally, aggregate with a particle size between about
0.75 and 10 mm, such as between about 1 and 5 mm, such as between
about 1 and 2 mm, may also added to a GUHPC mix at up to about 50
wt %, preferably together with fine aggregate. Examples of coarse
aggregate include, but are not limited to, crushed quartz, granite,
gneiss, basalt, limestone, and calcined bauxite sands.
[0095] Crushed granulated blast furnace slag having a particle size
between about 0.1 and 10 mm may also be used as aggregate in a
GUHPC mix. Stronger bonding between aggregate particles and the
geopolymer matrix may be observed in such mixes due to high
reactivity of furnace slag in alkaline solution.
[0096] Strength Enhancers
[0097] Optionally, at least one strength enhancer may be added into
the activator solution at up to about 2 wt %, such as from about 0
to 3 wt %, such as from about 0 to 2 wt %, such as from about 0.5
to 1.5 wt %, or such as about 0 to 1.5 wt %, such as about 0 to
0.75 wt % of the GUHPC mix. Any strength enhancer known in the art,
or combinations thereof, may be used. Exemplary strength enhancers
include, but are not limited to, sodium fluoride, potassium
fluoride, sodium sulfate, sodium oxalate, sodium phosphate and
related compounds, and aluminum hydroxide.
[0098] Fibers for Reinforcement
[0099] Optionally, fiber can be added to a GUHPC mix up to about 15
wt %, such as up to about 10%, such as up to about 7.5 wt %, in
order to secure desirable ductile behavior of the hardened product.
Exemplary fibers include short fibers such as: organic fibers
(e.g., polyvinyl alcohol fibers and polyacrylonitrile fibers);
glass fibers (e.g., basalt fibers); carbon fibers; and metal
fibers.
[0100] Metal fibers are preferred due to their substantial
ductility and the increased ductility they confer on a GUHPC
product. Metal fibers are generally chosen from steel fibers, such
as high strength steel fibers and stainless steel fibers. The
individual length of the metal fibers is generally at least 2 mm
and is preferably between about 10 and 30 mm. The ratio of length
to diameter of metal fibers used for reinforcement is typically
within the range of about 10 to 300, and is preferably within the
range of about 30 to 100. Fibers with a variable geometry (such as
being crimped, corrugated, or hooked at the end) may be used. The
bonding of metal fibers in the geopolymeric matrix may be improved
by treating the surfaces of the fibers my methods known in the art,
such as acidic etching or coating the fibers with ceramic layers.
Dramix.RTM. steel fibers (such as 13 mm in length and 0.20 mm in
diameter) from Bekaert Corporation are exemplary metal fibers which
were used by the Inventors to prepare certain exemplary GUHPC
products.
[0101] Water Reducers/Superplasticizer Solids
[0102] Optionally, water reducers or superplasticizer solids may be
used to decrease the amount of water needed for preparing an
activator solution for a GUHPC mix. Superplasticizer solids belong
to a new class of water reducers capable of reducing water content
by about 30% for Portland cement based concretes. More recent
superplasticizers include polycarboxylic compounds, such as
polyacrylates, although any superplasticizer known in the art may
be used.
[0103] If included, superplasticizer solids are preferably used at
up to about 5 wt %, such as up to about 2.5 wt %, such as up to
about 1.5 wt %.
[0104] Set Retarders
[0105] Optionally, one or more set retarders (e.g., boric acid,
certain commercial products such as Daratar 17 from
Grace-Constructions, etc.) may be included to extend setting times
of a GUHPC paste. Any set retarder known in the art may be included
at appropriate levels.
[0106] Generic Preparation Method and Summary of Constituents
[0107] In one embodiment, the activator solution is prepared by
dissolving silica fume in alkali hydroxide solution. Optionally,
the activator solution may be aged with intermittent stirring. The
dry constituents described above, except for the submicron filler,
are premixed in an appropriate mixer, such as intensive mixer.
Then, the alkaline activation solution, together with the
superplasticizer (if any) and/or strength enhancer (if any), are
poured into the dry mixture and mixed. With a near optimal W/C
ratio, the dry mixture turns into a granule like mixture, which
turns into a sand like mixture under continued mixing at high shear
rate, e.g., at about 250 revolutions per minute or higher.
Submicron filler, such as silica fume, is then added and mixed, and
the sand like mixture turns into a dough like mixture which finally
becomes a homogenous, workable, flowable, paste that is ready for
pouring. Short fibers (if any) are preferably added near the end of
the mixing process, such as along with the submicron filler or
later.
[0108] The geopolymeric ultrahigh performance concretes (GUHPC) of
the present invention may be manufactured by known methods, such as
known methods of mixing dry constituents with an activator
solution, shaping and placing (moulding, casting, injecting,
pumping, extruding, roller compacting, etc.), curing and hardening.
The process of curing GHUPC according to the present invention is
not subject to any particular limitations. Any ordinary curing
process may be used for cast in place and precast concretes.
[0109] The above constituents and their proportions in various
GUHPC mixes are compiled and presented Tables 1 and 2.
TABLE-US-00001 TABLE 1 Constituents and their proportions in GUHPC
mixes Constituent Range (wt %) Binder Reactive aluminosilicate or
reactive alkali- 10-50 earth aluminosilicate or both Filler 0-35
Aggregate 0-75 Activator M.sub.2O (M.dbd.K, Na, or both) 2-15
SiO.sub.2 2-15 Water 4-25 Strength enhancer 0-2 Fiber 0-15
Superplasticizer solids 0-5
TABLE-US-00002 TABLE 2 Constituents and their preferred proportions
in GUHPC mixes Range I Range II Type of materials Constituents (wt
%) (wt %) Binder Reactive aluminosilicate 0-30 2-15 Alkali-earth
aluminosilicate 2-40 8-25 Filler 2-35 2-25 Aggregate 15-75 30-60
Activator M.sub.2O (M.dbd.K, Na, or both) 2-10 2-8 SiO.sub.2 2-10
2-8 Water 5-20 7-15 Strength enhancer 0-1.5 .sup. 0-0.75 Fiber 0-10
0-7.5 Superplasticizer solids 0-2.5 0-1.5
[0110] Constraining Parameters
[0111] Constraining parameters and their respective ranges can be
used to define certain non-limiting formulations of GUHPC.
Constraining parameters are set for the specific constituents used
in the GUHPC mix.
[0112] In embodiments where metakaolin is used as a reactive
aluminosilicate, the metakaolin constraining parameters include a
set of molar ratios of SiO.sub.2/Al.sub.2O.sub.3,
M.sub.2O/Al.sub.2O.sub.3, and H.sub.2O/M.sub.2O, where M represents
one or more alkali metals (e.g., Na, K, Li) or alkali-earth metals.
The SiO.sub.2/Al.sub.2O.sub.3 molar ratio in metakaolin is about 2.
Alkali hydroxide and alkali silicate are added to the solution to
obtain the required values for the molar ratios characteristic of
an activation solution. These characteristic molar ratios are
SiO.sub.2/Al.sub.2O.sub.3 from about 3.0 to 6.0, such as from about
3.25 to 4.5, such as from about 3.5 to 4.0;
M.sub.2O/Al.sub.2O.sub.3 from about 0.7 to 1.5, such as from about
0.9 to 1.25, or about 1.0 to 1.35; and H.sub.2O/M.sub.2O from about
5.0 to 18.0, such as from about 5.0 to 14.0, such as about 6.0 to
10.0.
[0113] In embodiments where synthetic fly ash glass powder is used
as a reactive aluminosilicate; vitreous calcium aluminosilicate is
used as a reactive alkali-earth aluminosilicate; blast furnace slag
is used as a reactive alkali-earth aluminosilicate; or some
combination thereof, the constraining parameters are as follows.
The constraining parameters include a set of mass fractions of
M.sub.2O, SiO.sub.2, H.sub.2O, and molar ratio SiO.sub.2/M.sub.2O
that are used to formulate an activation solution. Both reactive
aluminosilicate and reactive alkali-earth aluminosilicate are
pozzolanic materials responsible for forming a geopolymer matrix.
Mass fractions of M.sub.2O or SiO.sub.2 of the pozzolanic materials
can range from about 0.03 to 0.15, such as about 0.05 to 0.10. The
SiO.sub.2/M.sub.2O molar ratio ranges from about 0.2 to 2.5, such
as about 0.8 to 1.5. The mass fraction of H.sub.2O ranges from
about 0.15 to 0.40, such as from about 0.25 to 0.30. Alkali metals
can be any of Na, K, or Li, or any combination, with Na
particularly useful for cost savings. The amounts of alkali
hydroxide, alkali silicate, and water needed for the reactive
components are summed up to formulate an activation solution
composition.
[0114] Constraining parameters for CKD as a reactive alkali-earth
aluminosilicate include the mass fractions of SiO.sub.2 (dissolved
silica or any source of amorphous silica material--e.g.,
micro-silica, silica fume, etc.), Al.sub.2O.sub.3 (dissolved
aluminate, alumina, aluminum hydroxides, etc.), and H.sub.2O. CKD
is rich in free lime and gypsum, showing strong hydraulic
pozzolanic property. The mass fractions of SiO.sub.2 range from
about 0.05 to 0.75, such as about 0.25 to 0.5. The mass fraction of
Al.sub.2O.sub.3 ranges from about 0.00 to 1.0, and the mass
fraction of water ranges from about 0.15 to 0.6, preferably from
about 0.25 to 0.35. The resulting gel compositions will include
CSH, ettringite, CASH, and AAS.
[0115] No constraining parameters are required for use of one or
more of fumed silica, precipitated silica, alumina, or calcined
zeolite as reactive filler if these reactive fillers are added into
a GUHPC mix in a small amount, e.g., less than about 2 wt % of the
mix. However, if the combined reactive fillers exceed 2 wt % of the
mix, certain constraining parameters need be applied. Mass
fractions of M.sub.2O for the indicated reactive fillers can range
from about 0.0 to 0.10, such as about 0.025 to 0.05. The mass
fraction of H.sub.2O ranges from about 0.0 to 0.15, such as from
about 0.025 to 0.05.
[0116] In embodiments where fly ash is used as reactive filler,
additional soluble silica may be added to the activator solution
with mass fractions of SiO.sub.2 of the reactive fillers ranging
from about 0.0 to 0.10, such as about 0.025 to 0.05. The molar
SiO.sub.2/M.sub.2O ranges from about 0.2 to 2.5, such as about 0.8
to 1.5.
[0117] The water to geopolymer solids mass ratio (W/C) is a very
important parameter for a GUHPC mix. As used herein, the term
"geopolymer solids" is defined as sum of the masses of reactive
constituents in the binder (i.e., reactive aluminosilicate and/or
reactive alkali earth aluminosilicate) and masses of alkali oxide
and silicon dioxide dissolved in the activator. The W/C ratio is
determined by a set of constraining parameters such as the molar
ratio H.sub.2O/M.sub.2O for metakaolin (if present), mass fraction
of H.sub.2O for reactive alkali-earth aluminosilicate and other
reactive aluminosilicate materials other than metakaolin (if any),
mass fraction of H.sub.2O for reactive fillers, as well as whether
and how much a superplasticizer is applied. In certain examples
presented herein, masonry sand with moisture of about 2.5 wt % is
used as a fine aggregate. If the moisture content of the fine
aggregate deviates from about 2.5 wt %, the mix must be corrected
for the difference of H.sub.2O. Typically, W/C ratios in GUHPC
mixes range from about 0.12 to 0.60, such as about 0.20 to 0.50,
such as about 0.30 to 0.45.
[0118] Table 3 shows general constraints and preferred values used
to formulate the activator solution for a GUHPC mix.
TABLE-US-00003 TABLE 3 Constraints and preferred ranges for
activator solution Preferred Constituents Ratio or Material Range
Range Reactive SiO.sub.2/Al.sub.2O.sub.3 3.00-5.00 3.50-3.90
aluminosilicate M.sub.2O/Al.sub.2O.sub.3 0.70-1.50 1.00-1.35 (molar
ratio) H.sub.2O/M.sub.2O 5-18 6.0-10.0 (M.dbd.K, Na, or both)
Reactive H.sub.2O/BFS* 0.15-0.40 0.25-0.30 alkali-earth
SiO.sub.2/BFS* 0.03-0.15 0.07-0.09 aluminosilicate M.sub.2O/BFS*
0.03-0.15 0.07-0.09 (mass ratio) (M.dbd.K, Na, or both) Reactive
fillers H.sub.2O/reactive filler 0.-0.15 0.025 (mass ratio) (e.g.
fly ash) M.sub.2O/reactive filler 0-0.05 0-0.025 (e.g. fly ash)
*BFS represents reactive alkali-earth aluminosilicate
[0119] Formulating GUHPC Mix
[0120] The following is a general approach to formulate a GUHPC
mix. Firstly, the weight percents of aggregate, filler, fiber (if
any), and superplasticizer solids (if any) are prescribed.
Secondly, weight percents of the reactive alkali-earth
aluminosilicate and the reactive aluminosilicate are set with a
desired mass ratio. Thirdly, proportions of aggregate, filler, and
binder may then by optimized in terms of the maximum density
theory. The composition of an activation solution is formulated
based on a set of constraining parameters and their respective
ranges for the constituents (i.e., reactive aluminosilicate,
reactive alkali-earth aluminosilicate, and certain reactive
fillers) by summing the needed amounts of alkali hydroxide,
dissolved silica, and/or dissolved alumina (if any), and water.
Finally, binder (reactive aluminosilicate and/or reactive
alkali-earth aluminosilicate), filler (if any), aggregate (if any),
fiber (if any), superplasticizers (if any), set retarders (if any)
and the activation solution are then normalized so that the total
of the GUHPC mix composition amounts to 100% by weight.
[0121] In principle, the performance of GUHPC is at least partially
dependent on the packing density of all of the particles from the
dry constituents, including reactive aluminosilicate, reactive
alkali earth aluminosilicate, aggregate, and filler. Because GUHPC
products may be manufactured with locally available materials, it
is beneficial to determine packing densities of trial samples with
different proportions of constituents by use of both dry and wet
packing methods. Compositions with higher particle packing
densities may then be subject to further optimization
processes.
[0122] Characteristic ratios of an activation solution include the
W/C ratio; the activator to geopolymer solids ratio; the alkali
oxide to geopolymer solids ratio; the soluble silica to geopolymer
solids ratio; and the soluble silica to alkali oxide ratio, all by
weight. The preferred ranges in these characteristic ratios are
determined by constraining parameters and their respective ranges
set for each of the GUHPC components where they apply.
[0123] The M.sub.2O (M=K, Na) to geopolymer solids ratio by weight
is generally in the range of about 0.01 to 0.25, such as about 0.02
to 0.15, such as about 0.05 to 0.10. The SiO.sub.2 to geopolymer
solids ratio is generally in the range of about 0.01 to 0.25, such
as about 0.03 to 0.25, such as about 0.02 to 0.20, such as 0.05 to
0.15. The SiO.sub.2 to Na.sub.2O ratio by weight is generally in
the range of about 0.1 to 2.0, such as about 0.5 to 1.5, such as
about 0.75 to 1.25. The activator to geopolymer solids ratio by
weight is generally in the range of about 0.20 to 1.25, such as
about 0.50 to 1.0. The activator to total solid ratio is generally
in the range of about 0.05 to 0.70, such as about 0.30 to 0.50. For
an activation solution, the preferred metal silicate is a mixture
of alkali silicates, such as K and Na with mass ratios of
K.sub.2O/Na.sub.2O from about 0 to 5; and the preferred alkali
hydroxide is a mixture of alkali hydroxides, such as K and Na with
mass ratios of K.sub.2O/Na.sub.2O from about 0.1 to 3.
[0124] Molar concentrations of alkaline hydroxide (e.g., KOH and
NaOH) in activator solution are generally in the range from about 5
to 15 M, preferably from about 7.5 to 12 M. The moisture present in
the aggregate is generally included for such calculations.
[0125] Activator solution ranges from about 10 wt % to about 40 wt
% of the concrete mix.
[0126] Manipulation of the constituent proportions within given
ranges (see, e.g., Table 1) allows for optimization of the GUHPC
mix compositions to achieve rapid strength growth and high final
strength. GUHPC mixes described herein may be formulated for
applications at ambient temperatures, or specifically formulated
for any application at any other temperature commonly applied in
construction industry, such as for pre-cast applications which
usually require curing at elevated temperatures to achieve high
production rates. One advantage of the GUHPC mixes described herein
is that, in addition to the high compressive strength of the final
product, thermal curing may not be necessary. The curing
temperature may be lower than those for conventional UHPC. For
example, curing can be carried out at less than or equal to about
250.degree. C., such as less than or equal to about 100.degree. C.,
such as less than or equal to about 75.degree. C., such as less
than or equal to about 50.degree. C., such as less than or equal to
about 45.degree. C., such as less than or equal to about 30.degree.
C., such as less than or equal to about 25.degree. C., such as less
than or equal to about 20.degree. C.
[0127] Initial setting time for GUHPC mixes described herein may be
from about 0.5 to about 3 hours, such as about 0.5 to 1 hour. After
the composition is set, it is cured for 24 hours or more, such as
24 hours to one week or longer, at a curing temperature between
about 20.degree. C. and about 75.degree. C. Desired setting times
can be achieved by optimization of binder and filler composition
(e.g., by selecting binder and filler compositions with different
reactivities in alkaline solutions), or by other methods known in
the art.
[0128] The following Examples serve to illustrate the invention.
These Examples are in no way intended to limit the scope of the
methods.
EXAMPLES
[0129] In the following Examples, all GUHPC pastes were cured at
room temperatures, e.g., at about 25.degree. C., except were other
curing temperatures are specified.
[0130] Masonry sand from Aggregates Industries was used as fine
aggregate which has a particle size between 50 and 600 .mu.m with a
median size of about 250 .mu.m. The moisture in the fine aggregate
was about 2.5 wt % at ambient temperature. The moisture in the fine
aggregate was included to calculate molar concentrations of alkali
hydroxide and water to geopolymeric solids ratio. Actual moisture
deviation from 2.5 wt % was corrected.
[0131] #4 QROK was used as coarse quartz sand having a particle
size between 0.6 and 1.7 mm, and Min U-SIL.RTM. was used as crushed
quartz powder having a particle size between 1 to 25 .mu.m with a
median diameter of about 5 .mu.m. Both quartz products were from
U.S. Silica. Metakaolin (Kaorock) was from Thiele Kaolin Company,
Sandersville, Ga. The metakaolin had a particle size between 0.5
and 50 .mu.m with 50 vol % less than 4 .mu.m.
[0132] Ground granulated blast furnace slag grade 120 (NewCem Slag
cement) was from Lafarge, North America Inc. (Baltimore Terminal).
The furnace slag had a particle size between 0.5 to 60 .mu.m, with
50 vol % less than 7 .mu.m.
[0133] Silica fume, an industrial waste product from Fe--Si
alloying, was from Norchem Inc. The silica fume contained 2.42 wt %
carbon. The silica fume was used to prepare activator solutions by
dissolving silica fume in alkali hydroxide solution, or added as
submicron reactive filler.
[0134] One Class F fly ash (Micron.sup.3) was from Boral Material
Technologies Inc. The Boral fly ash had a particle size between 0.5
and 125 .mu.m with 50 vol % below 15 .mu.m. Another Class F fly ash
from Brandon Shores Power Station, Baltimore, Md., was from
Separation Technologies LLC. The Brandon Shores fly ash had lower
CaO (0.9 wt %) and a low Loss of Ignition (<1.5 wt %) and was
marketed under ProAsh. The Brandon Shores fly ash had a particle
size between 0.6 and 300 .mu.m with 50 vol % below 26 .mu.m.
Another Class F fly ash from Limestone Power Station, Jewett, Tex.,
was from Headwater Resources. The Jewett fly ash contained about 12
wt % CaO and had a particle size between 0.5 and 300 .mu.m with 50
vol % below 15 .mu.m. Dramix.RTM. steel fibers (13 mm in length and
0.20 mm in diameter) from Bekaert Corporation were used to improve
ductility.
[0135] Compressive strength was measured on a Test Mark CM-4000-SD
compression machine, following the ASTM C39/C 39M method. During
the testing, all samples were capped with rubber pads because the
top and bottom surfaces were not sufficiently plane-parallel for
bare measurement.
Example 1
[0136] KOH (90%) and NaOH (98%) were dissolved in tap water to make
alkaline solution using a mechanical stirrer, and silica fume was
dissolved in the KOH and NaOH solution. The silica fume from
Norchem Inc. contained about 2.42 wt % carbon. The activator
solution was black due to undissolved carbon. The activator
solution was aged for about 2 days before sample preparation.
[0137] Masonry sand with about 2.5 wt % moisture was used as fine
aggregate.
[0138] To prepare the GUHPC, the following constituents were first
mixed dry:
[0139] Metakaolin as reactive aluminosilicate (12.65 wt %),
[0140] Ground granulated blast furnace slag as alkali-earth
aluminosilicate (32.65 wt %),
[0141] Calcined zeolite 13.times. and silica fume as reactive
fillers (total 2 wt %), and
[0142] Masonry sand as fine aggregate (19.00 wt %).
[0143] Then, an activator was prepared by mixing:
[0144] Na.sub.2O (2.52 wt %) as NaOH,
[0145] K.sub.2O (6.18 wt %) as KOH,
[0146] SiO.sub.2 (8.44 wt %) as silica fume,
[0147] H.sub.2O (16.55 wt %), and
[0148] strength enhancers.
[0149] Strength enhancers used in the mixture included aluminum
hydroxide, sodium carbonate, sodium phosphate, sodium sulfate,
sodium oxalate and fluoride. Total addition was about 1.25 wt % of
the concrete mix. These were dissolved in water prior to use.
[0150] The activator solution was mixed with the premixed dry
constituents with a UNITEC EHR23 handheld mixer (maximum speed 275
rpm). During mixing, the following stages were observed: dry
mixture, sand-like mixture, granule-like mixture, dough-like
mixture, and finally the dough-like mixture became a thin paste
that could be poured, indicating that the mix had a near optimal or
optimal W/C ratio. The workable time of the final stage (the thin
paste) was about 50 min.
[0151] The paste was filled into cylindrical molds (2 by 4 inches),
vibrated while filling for about 3 minutes for bubbles to escape,
and then cured at room temperature. After 24 hours, the cylinders
were de-molded and stored at room temperature. After curing for 28
days, compressive strength of the samples was measured to be 23341
psi.
Example 2
[0152] A second exemplary GUHPC was prepared as follows.
[0153] KOH (90%) and NaOH (98%) were dissolved in tap water to make
alkaline solution using a mechanical stirrer, and high purity
silica fume (about 99.5 wt %) from Cabot Corporation was dissolved
in the KOH and NaOH solution.
[0154] Sodium fluoride, used as a strength enhancer, was first
dissolved in tap water. The addition was about 0.5 wt % of the
concrete mix.
[0155] The following constituents (unless otherwise indicated,
obtained from the sources indicated above) were mixed dry:
[0156] Metakaolin as reactive aluminosilicate (12.87 wt %),
[0157] Ground granulated blast furnace slag as alkali-earth
aluminosilicate (33.20 wt %),
[0158] Calcined zeolite 13.times. and silica fume as reactive
fillers (total 2 wt %),
[0159] Sodium fluoride as strength enhancer (about 0.6 wt % of the
dry GUHPC), and
[0160] Masonry sand as fine aggregate (19.00 wt %).
[0161] Then, an activator was prepared by mixing:
[0162] Na.sub.2O (2.57 wt %) as NaOH,
[0163] K.sub.2O (6.28 wt %) as KOH,
[0164] SiO.sub.2 (8.59 wt %) as silica fume, and
[0165] H.sub.2O (15.50 wt %).
[0166] Superplasticizer ADVA 140M from Grace Constructions was
added to the activator before mixing with the premixed dry
components. The dose of superplasticizer was about 1500 ml per 100
kg dry product.
[0167] During mixing of the dry constituents with the activator
solution, the same stages (dry mixture, sand-like mixture,
granule-like mixture, dough-like mixture, and finally a thin paste)
were observed. The workable time of the final stage (the thin
paste) was about 50 min. As in Example 1, samples were poured,
cured at room temperature, de-moulded after curing 24 hours, and
stored at room temperature. After curing for 28 days, compressive
strength of the samples was measured to be 21248 psi.
Example 3
[0168] Using the same procedure described in Example 1, with no
superplasticizer added, additional GUHPC samples (Samples 3-9) were
prepared to test effect of individual strength enhancers in
activator solution. Individual strength enhancers evaluated in
Samples 2-4 and 6-9 were tin fluoride, sodium fluoride, sodium
oxalate, sodium sulfate, and aluminum hydroxide. Each addition was
about 0.5 wt % of the concrete mixes. No strength enhancer was
included in Sample 5. The compressive strengths were measured after
curing for 28 days. All samples measured above 20,000 psi in
compressive strength. The composition, W/C, concentration of alkali
hydroxides in activator solution, and compression strength of the
additional samples are shown in Table 4.
TABLE-US-00004 TABLE 4 Composition (wt %), W/C, molar concentration
of alkali hydroxides in activator solution, and compression
strength (psi) from GUHPC samples* Dry components Activator Sample
MK BFS SFF ZT Sand K.sub.2O SiO.sub.2 Na.sub.2O Water Sum W/C
(K,Na)OH M psi #3 13.02 33.60 1.01 1.01 19.23 5.15 8.69 2.60 15.69
100.00 0.26 11.94 21049 #4 12.78 32.97 1.01 1.01 19.23 5.07 8.54
2.55 16.85 100.00 0.28 10.95 20693 #5 12.80 33.03 1.01 1.01 19.23
5.07 8.55 2.55 16.75 100.00 0.28 11.03 20617 #6 12.80 33.03 1.01
1.01 19.23 5.07 8.55 2.55 16.75 100.00 0.28 11.03 20144 #7 12.80
33.03 1.01 1.01 19.23 5.07 8.55 2.55 16.75 100.00 0.28 11.03 20989
#8 12.80 33.03 1.01 1.01 19.23 5.07 8.55 2.55 16.75 100.00 0.28
11.03 20281 #9 12.80 33.03 1.01 1.01 19.23 5.07 8.55 2.55 16.75
100.00 0.28 11.03 20700 *SFF = silica fume filler; ZT = zeolite;
Na.sub.2O and K.sub.2O added as hydroxides, and SiO.sub.2 added as
silica fume (e.g., Fe--Si alloying waste product) to prepare
activator solutions
Example 4
[0169] Using the same procedure described in Example 1, additional
GUHPC samples (Samples 10-16) were prepared. Their compressive
strengths were measured after curing for 28 days. About 1.2 wt % of
superplasticizer solids (ADVA Cast 575 from Grace Constructions)
was added to reduce water demand and to improve flowability of the
pastes. Strength enhancers including sodium fluoride, sodium
oxalate, sodium sulfate, and aluminum hydroxide together were added
at about 1.15 wt %. In Sample 13, steel fiber from Bekaert
Corporation at about 2 wt % (not shown in Table 5) was added at the
last step of mixing to improve ductility. The composition, W/C,
concentration of alkali hydroxides in activator solution, and
compressive strengths of the additional samples are shown in Table
5.
TABLE-US-00005 TABLE 5 Composition (wt %), W/C, molar concentration
of alkali hydroxides in activator solution, and compression
strength (psi) from additional GUHPC samples* Dry components
Activator solution Sample MK BFS SFF ZT Sand K.sub.2O SiO.sub.2
Na.sub.2O SP Water Sum W/C (K,Na)OH M psi #10 10.46 27.00 2.00 1.00
29.97 4.66 6.98 2.15 1.20 14.58 100.00 0.30 10.97 21653 #11 9.67
24.95 2.00 1.00 34.97 4.32 6.46 2.00 1.20 13.44 100.00 0.30 10.90
21970 #12 8.87 22.89 2.00 1.00 39.97 3.95 5.92 1.84 1.20 12.35
100.00 0.31 10.74 21930 #13 8.44 21.77 1.97 0.99 39.46 4.17 5.64
1.76 1.18 12.65 100.00 0.33 10.65 20468 #14 11.26 29.07 2.00 1.00
24.98 5.01 7.51 2.30 1.20 15.67 100.00 0.30 11.09 20454 #15 12.06
31.12 2.00 1.00 19.98 5.38 8.05 2.46 1.20 16.76 100.00 0.29 11.22
20488 #16 7.17 18.50 1.97 0.98 49.23 3.20 4.78 1.51 1.18 11.48
100.00 0.36 9.17 19326 *SFF = silica fume filler; ZT = zeolite; SP
= superplasticizer solids; Na.sub.2O and K.sub.2O added as
respective hydroxides, and SiO.sub.2 added as silica fume (e.g.,
Fe--Si alloying waste product) to prepare activator solutions
Example 5
[0170] Using the same procedure described in Example 1, additional
GUHPC samples (Samples 17-33) were prepared. The samples were cured
at room temperature and their compressive strengths were measured
after curing for 28 days. Crushed quartz (QZ) with a mean particle
size of 15 .mu.m from U.S. Silica was used as a weak reactive
filler to improve packing density of the products. No
superplasticizer was added. In Samples 18, 23, 29, and 32, about 2
wt % steel fiber from Bekaert Corporation was added to improve
ductility. In Samples 20-22, molar Fluoride (F)/Si in activator
solution was increased from 0.2, to 0.3, and 0.4, respectively, to
test effect of fluoride concentration on the performance.
Correspondingly, sodium fluoride was increased from 0.90, 1.35, to
1.79 wt % of the concrete mix. The composition, W/C, concentration
of alkali hydroxides in activator solution, and compressive
strengths of the additional samples are shown in Table 6.
TABLE-US-00006 TABLE 6 Composition (wt %), W/C, molar concentration
of alkali hydroxides in activator solution, and compression
strength (psi) from additional GUHPC samples* Dry components
Activator Sample MK BFS SFF ZT QZ Sand Fiber K.sub.2O SiO.sub.2
Na.sub.2O Water Sum (K,Na)OH M W/C psi #17 8.84 22.81 2.98 -- 6.95
34.75 -- 3.96 5.91 1.79 12.03 100.00 11.98 0.30 24094 #18 7.48
19.29 2.95 -- 7.87 39.33 1.97 3.33 4.99 1.52 11.29 100.00 9.75 0.34
24961 #19 9.63 24.85 3.00 -- 5.99 29.97 -- 4.33 6.44 1.94 13.84
100.00 10.59 0.31 20469 #20 9.63 24.85 3.00 -- 5.99 29.97 -- 4.33
6.44 1.94 13.84 100.00 10.59 0.31 24212 #21 9.63 24.85 3.00 -- 5.99
29.97 -- 4.33 6.44 1.94 13.84 100.00 10.59 0.31 23370 #22 9.63
24.85 3.00 -- 5.99 29.97 -- 4.33 6.44 1.94 13.84 100.00 10.59 0.31
20910 #23 7.28 18.79 1.96 0.98 7.84 39.19 1.96 3.47 4.87 1.53 12.13
100.00 9.39 0.36 24150 #24 7.68 19.82 1.98 0.99 7.93 39.64 -- 3.59
5.13 1.61 11.62 100.00 10.17 0.33 23459 #25 10.26 26.47 1.99 0.99
4.97 24.86 -- 4.64 6.86 2.25 16.71 100.00 9.87 0.34 21929 #26 11.37
29.33 1.97 0.98 3.94 19.69 -- 5.27 7.59 2.32 17.54 100.00 10.36
0.32 20657 #27 6.65 17.15 1.97 0.98 8.86 44.28 -- 3.18 4.45 1.41
11.08 100.00 9.27 0.37 26005 #28 6.48 16.73 2.00 1.00 9.00 45.00 --
3.19 4.33 1.61 10.65 100.00 10.16 0.36 24698 #29 5.95 15.36 2.00
1.00 9.00 45.00 2.00 3.00 3.97 1.67 11.05 100.00 9.65 0.41 23188
#30 5.70 14.71 1.97 0.98 9.84 49.19 -- 2.76 3.81 1.23 9.82 100.00
8.89 0.39 21717 #31 8.39 21.64 1.99 0.99 6.96 34.80 -- 3.82 5.61
1.86 13.94 100.00 9.53 0.36 22955 #32 5.12 13.21 2.00 -- 10.00
50.00 2.00 2.95 3.49 1.24 10.00 100.00 9.12 0.43 21487 #33 4.29
11.07 1.95 1.00 10.71 53.53 -- 2.39 2.86 1.13 11.10 100.00 7.03
0.57 21456 *SFF = silica fume filler; ZT = zeolite; Fiber = steel
fiber; QZ = crushed quartz; Na.sub.2O and K.sub.2O added as
hydroxides, and SiO.sub.2 added as silica fume (e.g., Fe--Si
alloying waste product) to prepare activator solutions
Example 6
[0171] Using the same procedure described in Example 1, additional
GUHPC samples (Samples 34-42) were prepared. The samples were cured
at room temperature and their compressive strengths were measured
after curing for 28 days. In these samples, masonry sand was used
as the fine aggregate, and silica fume and zeolite together were
added as reactive fillers. Strength enhancers including sodium
fluoride, sodium oxalate, sodium sulfate, and aluminum hydroxide
together were added at about 1.15 wt % of the concrete mix in
Samples 34-40. Sodium fluoride and sodium oxalate were added at
about 0.8 wt % of the concrete mix in Samples 41 and 42. No
superplasticizer was added. In Sample 40, steel fiber from Bekaert
Corporation was added to improve ductility. The composition, W/C,
concentration of alkali hydroxides in activator solution, and
compressive strengths of the additional samples are shown in Table
7.
TABLE-US-00007 TABLE 7 Composition (wt %), W/C, molar concentration
of alkali hydroxides in activator solution, and compression
strength (psi) from additional GUHPC samples* Dry components
Activator Sample MK BFS SFF ZT Sand Fiber K.sub.2O SiO.sub.2
Na.sub.2O Water Sum (K,Na)OH M W/C psi #34 10.20 26.32 2.00 1.00
29.97 -- 4.56 6.94 2.24 16.77 100.00 9.65 0.35 20667 #35 9.41 24.28
1.99 0.99 34.81 -- 4.62 6.41 2.07 15.41 100.00 10.14 0.35 20672 #36
8.60 22.20 2.00 1.00 39.96 -- 3.88 5.86 2.07 14.44 100.00 9.66 0.36
20746 #37 7.85 20.26 2.00 1.00 44.97 -- 3.52 5.35 1.91 13.15 100.00
9.55 0.37 20775 #38 11.16 28.79 2.00 1.00 25.00 -- 5.47 7.60 2.43
16.55 100.00 11.33 0.31 20414 #39 7.14 18.42 2.00 1.00 50.12 --
3.72 4.86 1.70 11.03 100.00 10.89 0.34 21432 #40 5.96 15.38 2.00
1.00 55.00 2.00 3.29 4.06 1.46 9.85 100.00 10.43 0.37 20400 #41
7.13 18.40 2.00 1.00 50.00 -- 3.78 4.76 1.58 11.35 100.00 10.41
0.35 21296 #42 6.30 16.26 2.00 1.00 55.00 -- 3.39 4.21 1.49 10.35
100.00 10.23 0.37 20475 *SFF = silica fume filler; ZT = zeolite;
Fiber = steel fiber; Na.sub.2O and K.sub.2O added as respective
hydroxides, and SiO.sub.2 added as silica fume (e.g., Fe--Si
alloying waste product) to prepare activator solutions
Example 7
[0172] Using the same procedure described in Example 1, additional
GUHPC samples (Samples 43-48) were prepared. The samples were cured
at room temperature and their compressive strengths were measured
after curing for 28 days. In these samples, masonry sand was used
as the fine aggregate, and silica fume and/or zeolite were added as
reactive fillers. Strength enhancers including sodium fluoride,
sodium oxalate, sodium sulfate, and aluminum hydroxide together
were added at about 1.15 wt % of the concrete mix in Samples 43-45.
Sodium fluoride and/or sodium oxalate were added as strength
enhancers at about 0.7 wt % of the concrete mix in Samples 46-48.
No superplasticizer was added. Class F fly ash from Boral Material
Technologies was used as reactive filler. The composition, W/C,
concentration of alkali hydroxides in activator solution, and
compressive strengths of the additional samples are shown in Table
8.
TABLE-US-00008 TABLE 8 Composition (wt %), W/C, molar concentration
of alkali hydroxides in activator solution, and compression
strength (psi) from additional GUHPC samples* Dry components
Activator Sample MK BFS SFF ZT FAF Sand K.sub.2O SiO.sub.2
Na.sub.2O Water Sum (K,Na)OH M W/C psi #43 4.61 11.90 2.00 -- 10.00
55.00 2.50 3.14 1.70 9.15 100.00 10.26 0.44 22624 #44 6.26 16.15
2.00 1.00 9.00 45.00 3.07 4.34 1.73 11.45 100.00 9.63 0.40 22862
#45 7.16 18.49 2.00 1.00 8.00 40.00 3.52 4.97 1.91 12.95 100.00
9.77 0.39 22235 #46 4.77 12.32 2.96 -- 8.89 54.36 2.65 3.09 1.46
9.52 100.00 9.50 0.45 21652 #47 4.68 12.08 2.00 -- 10.00 55.00 2.58
3.19 1.72 8.75 100.00 10.88 0.42 19970 #48 4.39 11.33 2.00 2.00
5.00 60.00 2.46 2.99 1.59 8.25 100.00 10.60 0.43 23007 *SFF =
silica fume filler; ZT = zeolite; FFA = Class F fly ash; Na.sub.2O
and K.sub.2O added as hydroxides, and SiO.sub.2 added as silica
fume (e.g., Fe--Si alloying waste product) to prepare activator
solutions
Example 8
[0173] Using the same procedure described in Example 1, additional
GUHPC samples (Samples 49-52) were prepared. The samples were cured
at room temperature and their compressive strengths were measured
after curing for 28 days. In these samples, masonry sand was used
as fine aggregate, and silica fume and/or zeolite were added as
reactive filler. Crushed quartz (QZ) with a mean particle size of
15 .mu.m from U.S. Silica was used as weak reactive filler.
Additionally, coarse quartz sand (#4 Q-ROK) from U.S. Silica was
added to improve packing density. Strength enhancers used in these
samples included aluminum hydroxide, sodium carbonate, sodium
phosphate, sodium sulfate, sodium oxalate, and fluoride. Total
addition of strength enhancers was about 0.85 wt % of the concrete
mix in Samples 49 and 51. Sodium fluoride alone was added as a
strength enhancer at about 0.25 wt % of the concrete mix in Samples
50 and 52. No superplasticizer was added. The composition, W/C,
concentration of alkali hydroxides in activator solution, and
compressive strengths of the additional samples are shown in Table
9.
TABLE-US-00009 TABLE 9 Composition (wt %), W/C, molar concentration
of alkali hydroxides in activator solution, and compression
strength (psi) from additional GUHPC samples* Dry components
Activator Sample MK BFS SFF CA QZ Sand K.sub.2O SiO.sub.2 Na.sub.2O
Water Sum (K,Na)OH M W/C psi #49 5.84 15.06 2.98 35.11 6.50 14.96
3.13 4.05 1.35 11.02 100.00 9.66 0.36 21892 #50 7.54 19.47 1.99
29.61 5.48 12.61 4.12 5.23 1.29 12.65 100.00 9.96 0.38 22699 #51
6.68 17.24 2.98 32.06 5.94 13.65 3.43 4.63 1.54 11.86 100.00 10.04
0.34 20169 #52 5.06 13.05 2.98 38.17 7.07 16.26 2.73 3.51 1.25 9.94
100.00 9.49 0.40 20561 *SFF = silica fume filler; CA = coarser
aggregate; QZ = crushed quartz; Fiber = steel fiber; Na.sub.2O and
K.sub.2O added as respective hydroxides, and SiO.sub.2 added as
silica fume (e.g., Fe--Si alloying waste product) to prepare
activator solutions
Example 9
[0174] Using the same procedure described in Example 1, additional
GUHPC samples (Samples 53-56) were prepared. The samples were cured
at room temperature and their compressive strengths were measured
after curing for 28 days. In these samples, masonry sand was used
as fine aggregate; and silica fume was added as submicron reactive
filer. Crushed quartz (QZ) from U.S. Silica was used as weak
reactive filler. Sodium fluoride (NaF) at about 0.25 wt % of the
concrete mix was added as a strength enhancer. No superplasticizer
was added. In Sample 55, steel fiber from Bekaert Corporation was
added to improve ductility. The composition, W/C, concentration of
alkali hydroxides in activator solution, and compressive strengths
of the additional samples are shown in Table 10.
TABLE-US-00010 TABLE 10 Composition (wt %), W/C, molar
concentration of alkali hydroxides in activator solution, and
compression strength (psi) from additional GUHPC samples* Dry
components Activator Sample MK FS SFF QZ Sand Fiber K.sub.2O
SiO.sub.2 Na.sub.2O Water Sum (K,Na)OH M W/C psi #53 6.51 16.80
2.00 9.00 45.00 -- 3.34 4.52 1.48 11.35 100.00 9.51 0.38 25072 #54
5.55 14.32 2.00 10.00 50.00 -- 2.97 3.85 1.27 10.05 100.00 9.20
0.40 25681 #55 4.91 12.67 2.93 9.76 48.78 1.95 2.83 3.41 1.21 11.56
100.00 7.76 0.51 20997 #56 5.88 15.17 2.94 13.71 41.14 -- 3.43 4.11
1.44 12.19 100.00 9.02 0.44 22154 *SFF = silica fume filler; QZ =
crushed quartz; Fiber = steel fiber; Na.sub.2O and K.sub.2O added
as hydroxides, and SiO.sub.2 added as silica fume (e.g., Fe--Si
alloying waste product) to prepare activator solutions
Example 10
[0175] Using the same procedure described in Example 1, additional
GUHPC samples (Samples 57-64) were prepared. The samples were cured
at room temperature and their compressive strengths were measured
after curing for 28 days. In these samples, masonry sand was used
as fine aggregate; and silica fume and/or zeolite were added as
reactive filler. Crushed quartz (QZ) from U.S. Silica was used as
weak reactive filler in Samples 62 and 64. The activator solutions
were prepared by using predominantly sodium hydroxide and
industrial waste silica fume from Norchem Inc. Strength enhancers
used in these samples included aluminum hydroxide, sodium
carbonate, sodium phosphate, sodium sulfate, sodium oxalate, and
fluoride. Total addition of strength enhancers was less than about
1.0 wt % of the concrete mix. These were dissolved in water prior
to dissolution of alkali hydroxides. No superplasticizer was added.
The composition, W/C, concentration of alkali hydroxides in
activator solution, and compressive strengths of the additional
samples are shown in Table 11.
TABLE-US-00011 TABLE 11 Composition (wt %), W/C, molar
concentration of alkali hydroxides in activator solution, and
compression strength (psi) from additional GUHPC samples* Dry
components Activator Sample MK BFS SFF ZT QZ Sand K.sub.2O
SiO.sub.2 Na.sub.2O Water Sum (Na,K)OH M W/C psi #57 9.93 25.62
1.98 0.99 -- 34.66 0.13 6.63 5.19 14.86 100.00 10.84 0.31 23804 #58
10.56 27.26 1.97 0.98 -- 29.51 0.39 7.06 5.53 16.74 100.00 10.69
0.34 20258 #59 8.99 23.21 1.96 0.98 -- 39.25 0.60 6.01 4.72 14.28
100.00 10.82 0.35 20529 #60 11.34 29.26 1.96 0.98 -- 24.55 0.58
7.58 5.93 17.82 100.00 11.05 0.34 20910 #61 12.10 31.22 1.96 0.98
-- 19.65 0.57 8.09 6.30 19.13 100.00 10.98 0.34 19760 #62 5.67
14.64 1.97 -- 9.87 49.35 0.42 3.83 3.49 10.76 100.00 10.13 0.43
22433 #63 7.55 19.49 2.00 -- -- 50.00 -- 5.05 4.16 11.75 100.00
10.32 0.36 21596 #64 6.52 16.82 1.96 -- 8.80 44.02 0.31 4.35 3.86
13.37 100.00 9.06 0.45 20898 *SFF = silica fume filler; QZ =
crushed quartz; Fiber = steel fiber; Na.sub.2O and K.sub.2O added
as respective hydroxides, and SiO.sub.2 added as silica fume (e.g.,
Fe--Si alloying waste product) to prepare activator solutions
Example 11
[0176] Using a procedure similar to that described in Example 1,
additional GUHPC samples (Samples 65-67) were prepared. The samples
were cured at room temperature and their compressive strengths were
measured after curing for 28 days. In these samples, masonry sand
was used as fine aggregate; and silica fume from Norchem Inc. was
used as submicron reactive filler. Crushed quartz (QZ) from U.S.
Silica was used as weak reactive filler in Samples 65 and 66. Class
F fly ash from Boral Material Technologies was used to replaced
crushed quartz powder in Sample 67. The activator solutions were
prepared by using commercially available sodium silicate solution
(Ru.TM. sodium silicate solution, PQ Inc.), instead of dissolving
silica fume in alkaline hydroxide solution. Sodium fluoride (NaF)
at about 0.25 wt % of the concrete mix was added as a strength
enhancer. No superplasticizer was added. The composition, W/C,
concentration of alkali hydroxides in activator solution, and
compressive strengths of the additional samples are shown in Table
12.
TABLE-US-00012 TABLE 12 Composition (wt %), W/C, molar
concentration of alkali hydroxides in activator solution, and
compression strength (psi) from additional GUHPC samples* Dry
components Activator Sample MK FS SFF QZ FAF Sand K.sub.2O
SiO.sub.2 Na.sub.2O Water Sum (Na,K)OH M W/C psi #65 6.77 17.46
1.98 8.89 -- 44.46 0.41 4.52 3.90 11.60 100.00 10.60 0.38 22485 #66
5.51 14.22 1.99 9.95 -- 49.74 0.13 3.68 3.70 11.08 100.00 9.90 0.45
20622 #67 5.58 14.41 1.99 -- 9.93 49.64 0.23 3.73 3.63 10.87 100.00
10.07 0.44 21448 *SFF = silica fume filler; QZ = crushed quartz;
FFA = Class F fly ash
Example 12
[0177] Using the same procedure as described in Example 1,
additional GUHPC samples (Samples 68-70) were prepared. The samples
were cured at room temperature and their compressive strengths were
measured after curing for 28 days. In these samples, masonry sand
was used as fine aggregate; and silica fume from Norchem Inc.
together with Class F fly ash from Boral Material Technologies were
used as reactive filler in Samples 68 and 70. Silica fume together
with crushed quartz (QZ) from U.S. silica was used as reactive
filler in Sample 69. The activator solutions were prepared by
dissolving silica fume from Norchem Inc. in alkaline hydroxide
solution with K.sub.2O/Na.sub.2O mass ratios at about 0.8. Sodium
fluoride (NaF) at about 0.25 wt % of the concrete mix was added as
a strength enhancer. No superplasticizer was added. The
composition, W/C, concentration of alkali hydroxides in activator
solution, and compressive strengths of the additional samples are
shown in Table 13.
TABLE-US-00013 TABLE 13 Composition (wt %), W/C, molar
concentration of alkali hydroxides in activator solution, and
compression strength (psi) from additional GUHPC samples* Dry
components Activator Sample MK FS SFF ZT QZ FAF Sand K.sub.2O
SiO.sub.2 Na.sub.2O Water Sum (Na,K)OH M W/C psi #68 6.31 16.29
2.98 0.99 -- 8.95 44.73 2.05 4.04 2.63 11.03 100.00 10.43 0.39
22653 #69 5.48 14.15 2.95 -- 9.82 -- 49.09 2.25 3.37 2.33 10.56
100.00 10.27 0.43 24582 #70 5.46 14.10 2.96 -- -- 9.88 49.39 2.02
3.51 2.45 10.23 100.00 10.47 0.42 23307 *SFF = silica fume filler;
ZT = zeolite; QZ = crushed quartz; FAF = Class F fly ash; Na.sub.2O
and K.sub.2O added as respective hydroxides, and SiO.sub.2 added as
silica fume (e.g., Fe--Si alloying waste product) to prepare
activator solutions
Example 13
[0178] Using a procedure similar to that described in Example 1,
additional GUHPC samples (Samples 71-88) were prepared. Mixing was
conducted with a high intensive mixer (K-Lab Mixer from Lancaster
Products). The samples were cured at room temperature and their
compressive strengths were measured after curing for 28 days. In
these samples, masonry sand was used as fine aggregate; and silica
fume from Norchem Inc. together with crushed quartz (QZ) from U.S.
Silica was used in Samples 71-79. Silica fume together with Class F
fly ash from Boral Material Technologies were used as reactive
filler in Samples 80 to 86. Zeolite was used as reactive filler in
Samples 87 and 88. The activator solutions were prepared by
dissolving silica fume from Norchem Inc. in alkaline hydroxide
solution with K.sub.2O/Na.sub.2O mass ratios at about 2 to about 3.
Steel fiber from Bekaert Corporation was added to improve ductility
in Samples 71, 73, 76, 81, 85, and 87. Sodium fluoride (NaF) at
about 0.25 wt % of the concrete mix was added as a strength
enhancer. No superplasticizer was added. The composition, W/C,
concentration of alkali hydroxides in activator solution, and
compressive strengths of the additional samples are shown in Table
14.
TABLE-US-00014 TABLE 14 Composition (wt %), W/C, molar
concentration of alkali hydroxides in activator solution, and
compression strength (psi) from additional GUHPC samples* Dry
components Activator Sample MK BFS SFF QZ FAF Sand Fiber K.sub.2O
SiO.sub.2 Na.sub.2O Water Sum (K,Na)OH M W/C psi #71 6.37 16.43
1.95 8.78 -- 43.88 2.50 3.38 4.41 1.44 10.87 100.00 9.90 0.37 23342
#72 6.56 16.92 2.01 9.04 -- 45.20 -- 3.49 4.54 1.49 10.75 100.00
10.27 0.36 25686 #73 6.39 16.50 1.96 8.81 -- 44.07 2.51 3.40 4.43
1.45 10.48 100.00 10.27 0.36 25918 #74 5.57 14.37 2.00 10.00 --
50.00 -- 3.00 3.86 1.34 9.85 100.00 9.64 0.39 21200 #75 5.64 14.55
2.00 10.00 -- 50.00 -- 3.08 3.92 1.36 9.45 100.00 10.21 0.37 24269
#76 5.50 14.19 1.95 9.75 -- 48.75 2.50 3.00 3.82 1.33 9.21 100.00
10.21 0.34 24652 #77 4.63 11.94 2.00 11.00 -- 55.00 -- 2.55 3.09
1.14 8.65 100.00 9.08 0.43 20638 #78 4.62 11.92 2.00 11.00 -- 55.00
-- 2.55 3.09 1.18 8.65 100.00 9.19 0.43 20700 #79 4.93 19.77 2.00
9.00 45.00 2.80 4.02 1.73 10.75 100.00 9.71 0.36 21132 #80 4.72
12.17 2.00 -- 10.00 55.00 -- 2.55 3.21 1.60 8.75 100.00 10.46 0.42
20343 #81 4.60 11.86 1.95 -- 9.75 53.62 2.50 2.49 3.13 1.56 8.53
100.00 10.46 0.42 21285 #82 4.70 12.13 2.00 -- 10.02 55.12 -- 2.92
3.21 1.35 8.55 100.00 10.64 0.41 22952 #83 4.58 11.82 1.95 -- 9.77
53.74 2.51 2.85 3.12 1.32 8.33 100.00 10.64 0.41 23807 #84 4.84
12.48 2.02 -- 10.08 55.46 -- 2.83 3.30 1.41 7.59 100.00 11.78 0.36
27415 #85 4.71 12.16 1.97 -- 9.83 54.06 2.52 2.76 3.21 1.38 7.40
100.00 11.78 0.35 23369 #86 4.80 12.37 2.00 -- 10.00 55.00 -- 2.81
3.27 1.40 8.35 100.00 11.30 0.38 20816 #87 6.18 15.95 1.95 --
0.97** 53.62 2.50 3.36 4.13 1.42 9.90 100.00 10.45 0.36 22688 #88
6.34 16.36 2.00 -- 01.00** 55.00 -- 3.45 4.24 1.46 10.15 100.00
10.45 0.36 21532 *SFF = silica fume filler; QZ = crushed quartz;
FAF = Class F fly ash; Na.sub.2O and K.sub.2O added as hydroxides,
and SiO.sub.2 added as silica fume (e.g., Fe--Si alloying waste
product) to prepare activator solutions **Zeolite
Example 14
[0179] Using the same procedure as described in Examples 71-88,
additional GUHPC samples (Samples 89-92) were prepared. Mixing was
conducted with a high intensive mixer (K-Lab Mixer from Lancaster
Products). Initial setting time was determined using a Vicat
system. The samples were cured at room temperature and their
compressive strengths were measured after curing for 3 hours, 6
hours, 1 day, 3 days, 7 days, 15 days, 21 days, and 28 days. In
these samples, masonry sand was used as fine aggregate; and silica
fume from Norchem Inc. together with Class F fly ash from Boral
Material Technologies were used as reactive filler in Example 89.
Silica fume together with crushed quartz (QZ) from U.S. Silica were
used as reactive filler in Samples 90-92. Activator solutions were
prepared by dissolving silica fume from Norchem Inc. in alkaline
hydroxide solution with K.sub.2O/Na.sub.2O mass ratios at about
2.2. No superplasticizer was added. Sodium fluoride (NaF) was added
as a strength enhancer. The composition, W/C, and concentration of
alkali hydroxides in activator solution of the additional samples
are shown in Table 15. Compressive strengths of Samples 89-92 at
the above indicated times are shown in Table 16. A plot of these
compressive strengths versus curing time is shown in FIG. 1.
TABLE-US-00015 TABLE 15 Composition (wt %), W/C, molar
concentration of alkali hydroxides in activator solution, and
compression strength (psi) from additional GUHPC samples* Dry
components Activator Sample MK BFS SFF QZ FFA Sand K.sub.2O
SiO.sub.2 Na.sub.2O Water Sum (K,Na)OH M W/C #89 4.82 12.43 2.01 --
10.04 55.24 2.82 3.28 1.41 7.94 100.00 11.30 0.38 #90 6.56 16.92
2.01 9.04 -- 45.20 3.49 4.54 1.49 10.75 100.00 10.27 0.36 #91 5.64
14.55 2.00 10.00 -- 50.00 3.08 3.92 1.36 9.45 100.00 9.96 0.37 #92
4.62 11.92 2.00 11.00 -- 55.00 2.55 3.09 1.18 8.65 100.00 9.19 0.43
*SFF = silica fume filler; QZ = crushed quartz; FAF = Class F fly
ash; Na.sub.2O and K.sub.2O added as hydroxides, and SiO.sub.2
added as silica fume (e.g., Fe--Si alloying waste product) to
prepare activator solutions
TABLE-US-00016 TABLE 16 Compressive strength (psi) of samples cured
for different times Initial/final Compressive strength (psi) Sample
setting times 3 hours 6 hours 24 hours 3 days 7 days 15 days 21
days 28 days #89 25/35 min 1095 2339 7026 13794 17360 21361 20949
23633 #90 63/75 min 1512 2846 7518 15278 19351 24268 22918 27211
#91 50/57 min 1312 2567 5780 14435 19221 25390 29104 25847 #92
42/68 min 1257 2016 6043 13823 17972 22080 23524 23174
Example 15
[0180] Using the same procedure as described in Example 13,
additional GUHPC samples (Samples 93-98) were prepared. Mixing was
conducted with a high intensive mixer (K-Lab Mixer from Lancaster
Products). The samples were cured at room temperature and their
compressive strengths were measured after curing for 3 hours, 6
hours, 1 day, 3 days, 7 days, 15 days, 21 days, and 28 days. In
these samples, masonry sand was used as fine aggregate; and silica
fume from Norchem Inc. together with low CaO Class F fly ash from
Brandon Shores Power Stations, Baltimore, Md. (Separation
Technologies) was used as reactive filler in Samples 93, 95, 97,
and 99. Silica fume from Norchem Inc. together with high CaO Class
F fly ash from Limestone Power Station, Jewett, Tex. (Headwater
Resources) was used as reactive filler in Samples 94, 96, 98, and
100. Activator solutions were prepared by dissolving silica fume
from Norchem Inc. in alkaline hydroxide solution with
K.sub.2O/Na.sub.2O mass ratios at about 2.2. No superplasticizer
was added. Sodium fluoride (NaF) at about 0.25 wt % of the concrete
mix was added as a strength enhancer. The composition, W/C, and
concentration of alkali hydroxides in activator solution the
additional samples are shown in Table 17. Compressive strengths of
Samples 93-98 at the above indicated times are shown in Table
18.
TABLE-US-00017 TABLE 17 Composition (wt %), W/C, molar
concentration of alkali hydroxides in activator solution, and
compression strength (psi) from additional GUHPC samples* Dry
component Activator (K,Na)OH Sample MK BFS SFF FFA Sand K.sub.2O
SiO.sub.2 Na.sub.2O Water Sum (M) W/C Type of FFA #93 5.64 14.55
2.00 10.00 50.00 3.08 3.92 1.36 9.45 100.00 10.21 0.38 Low CaO #94
5.64 14.55 2.00 10.00 50.00 3.08 3.92 1.36 9.45 100.00 10.21 0.38
High CaO #95 4.62 11.92 2.00 11.00 55.00 2.55 3.09 1.18 8.65 100.00
9.19 0.43 Low CaO #96 4.62 11.92 2.00 11.00 55.00 2.55 3.09 1.18
8.65 100.00 9.19 0.43 High CaO #97 4.80 12.37 2.00 10.00 55.00 2.81
3.27 1.40 8.35 100.00 10.78 0.38 Low CaO #98 4.80 12.37 2.00 10.00
55.00 2.81 3.27 1.40 8.35 100.00 10.78 0.38 High CaO #99 6.53 16.85
2.00 3.47 4.52 1.48 45.00 9.00 11.15 100.00 9.90 0.36 Low CaO #100
6.53 16.85 2.00 3.47 4.52 1.48 45.00 9.00 11.15 100.00 9.90 0.36
High CaO *SFF = silica fume filler; FAF = Class F fly ash;
Na.sub.2O and K.sub.2O added as respective hydroxides, and
SiO.sub.2 added as silica fume (e.g., Fe--Si alloying waste
product) to prepare activator solutions
TABLE-US-00018 TABLE 18 Compressive strength (psi) of samples cured
for different times Sample 3 hours 6 hours 24 hours 3 days 7 days
14 days 21 days 28 days #93 2497 5793 10468 16210 19322 24645 21210
22506 #94 2107 4403 10875 15940 19357 20634 21896 21982 #95 1430
2098 6663 12054 15287 19263 20143 ND #96 1233 2452 7263 12625 16905
20968 ND ND #97 1313 3207 9355 13420 16932 18048 20901 20873 #98
1666 3609 9179 -- 18621 20589 20649 ND #99 3243 6272 7795 12772
15381 20950 ND ND #100 2445 3453 8744 12625 18931 20968 ND ND ND =
not determined
[0181] The contents of the articles, patents, and patent
applications, and all other documents and electronically available
information mentioned or cited herein, are hereby incorporated by
reference in their entirety to the same extent as if each
individual publication was specifically and individually indicated
to be incorporated by reference. Applicants reserve the right to
physically incorporate into this application any and all materials
and information from any such articles, patents, patent
applications, or other physical and electronic documents.
[0182] The methods illustratively described herein may suitably be
practiced in the absence of any element or elements, limitation or
limitations, not specifically disclosed herein. Thus, for example,
the terms "comprising", "including," containing", etc. shall be
read expansively and without limitation. Additionally, the terms
and expressions employed herein have been used as terms of
description and not of limitation, and there is no intention in the
use of such terms and expressions of excluding any equivalents of
the features shown and described or portions thereof. It is
recognized that various modifications are possible within the scope
of the invention claimed. Thus, it should be understood that
although the present invention has been specifically disclosed by
preferred embodiments and optional features, modification and
variation of the invention embodied therein herein disclosed may be
resorted to by those skilled in the art, and that such
modifications and variations are considered to be within the scope
of this invention.
[0183] The invention has been described broadly and generically
herein. Each of the narrower species and subgeneric groupings
falling within the generic disclosure also form part of the
methods. This includes the generic description of the methods with
a proviso or negative limitation removing any subject matter from
the genus, regardless of whether or not the excised material is
specifically recited herein.
[0184] Other embodiments are within the following claims. In
addition, where features or aspects of the methods are described in
terms of Markush groups, those skilled in the art will recognize
that the invention is also thereby described in terms of any
individual member or subgroup of members of the Markush group.
* * * * *